Mackie Stereo Amplifier M1200 M1400 User Manual

M•1200/ M•1400

OWNER’SMANUAL

™

HIGH-CURRENTPOWERAMPLIFIERS

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Lend Me Your Ears

According to OSHA, any exposure in excess of

these permissible limits could result in some hear-

ing loss. To ensure against potentially dangerous

exposure to high sound pressure levels, it is recom-

Exposure to extremely high

noise levels may cause per-

manent hearing loss.

Individuals vary considerably mended that all persons exposed to equipment

in susceptibility to noise-induced hearing loss, but

nearly everyone will lose some hearing if exposed

to suffi-

capable of producing high sound pressure levels

(such as this amplification system) use hearing

protectors

ciently

intense

Duration Per Day Sound Level dBA,

Typical

Example

Duo in small club

while this

unit is in

In Hours

Slow Response

noise for a

period of

time. The

U.S.

Government’s

Occupa-

tional

operation.

Ear plugs

or protec-

tors in the

ear canals

Subway Train

1.5

0.5

100

102

105

110

115

Very loud classical music

Lori screaming at Ron about deadlines or over the

ears must

0.25 or less

Loudest parts at a rock concert

Safety and

Health Ad-

be worn

when oper-

ministration (OSHA) has specified the permissible ating this amplification system in order to prevent

noise level exposures shown in this chart.

a permanent hearing loss if exposure is in excess of

the limits set forth here.

INTRODUCTION

Thank you for choosing a Mackie Designs

power amplifier! We appreciate your vote of

confidence for the folks in Woodinville who

specialize in awesome and affordable audio.

The Mackie Designs M•1200/M•1400 Power

Amplifiers are designed to fulfill the amplifica-

tion needs of almost any type of application.

They boast a wealth of features you’d expect to

pay extra for — like subwoofer filtering, con-

stant directivity equalization, speaker-protecting

limiter, and gobs of ultra-clean power, to name

a few.

amplifier that performs better than conven-

tional designs when presented with adverse

conditions. One of the most difficult things for

a power amplifier to handle is clipping. Con-

ventional designs use lots of negative feedback

to provide stability and lower distortion. When

clipping occurs, this “feedback” causes high-

frequency sticking, keeping the amplifier

“latched” in the clipping state longer than nec-

essary. This results in painfully audible

distortion. Our Fast Recovery design eliminates

this high-frequency sticking and allows the am-

plifier to remain stable when powering highly

reactive loads at high volume levels.

You may wonder why a power amp even

needs an owner’s manual. After all, you just

plug in a few cables and power it up. Well, it’s

almost that simple. There’s just a few things

that we’d like you to be aware of, and we’ll dis-

cuss those right away — please see the Quick

Start on the next page.

Perhaps the most important feature of the

FR Series™ Power Amplifiers is the attention

to detail in every aspect of the design. At Mackie,

we know what it takes to be roadworthy. After

all, our mixers have traveled all over the world

under the worst of conditions, and we’ve applied

what we’ve learned to the mechanical design of

our amplifiers.

Roadworthiness is only part of the picture.

We know that reliability is paramount to sound

reinforcement. That’s why we use double-sided

thru-hole-plated fiberglass printed circuit

boards. That’s why our engineers have sub-

jected the amplifier to the most rigorous and

punishing tests imaginable, to fine-tune the

design and extend its limits beyond those of

ordinary amplifiers.

Then go ahead and read the entire manual.

The M•1200/M•1400 amplifiers have a wealth

of useful features, and each of them is explained

in detail.

Please write your serial number here for

future reference (i.e., insurance claims,

tech support, return authorization, etc.):

Fast Recovery — where the “FR” comes

from — is more than a buzzword. It is based on

real, proven design principles. The result is an

Part No. 820-062-00 Rev. A 12/96

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READTHISPAGE!

QUICK START

6. Determine which AMP MODE

is best

for your application:

I got ants in my pants and I got to dance!

•

STEREO mode (separate left and right

INSTALLATION

inputs, separate left and right outputs) is

the typical setup for amplifying stereo

signals.

The M•1200/M•1400

amps can be mounted in

•

MONO mode (sometimes called Dual-

any standard rack system

Mono mode – one mono input, two mono

outputs) is for sending a mono signal to

two different speaker sets, with separately-

adjustable level controls.

(see ), or placed horizon-

tally on a floor or table. The heavier internal

components are located towards the front of

the chassis to make it easier to hold the amp

by its front handles.

•

BRIDGE mode (sometimes called

IMPORTANT: The

M•1200/M•1400 amps

draw their ventilation air

in from the front and out

Bridged-Mono – one mono input, one mono

output) uses both sides of the amp to

double the power to one speaker set. An

M•1200 power amplifier, set to BRIDGE

mode, delivers 1200 watts (into 4 ohms).

The M•1400 delivers 1260 watts. Garsh!

through the side panels.

They need plenty of fresh air to stay cool.

DO NOT BLOCK THE VENTILATION PORTS

(see ).

Note: 4 ohms is the minimum impedance

you should connect to the amplifier in BRIDGE

mode. If you connect a lower impedance load

in BRIDGE mode, the SHORT LEDs may

light, putting the amplifier into PROTECT

mode.

CONNECTIONS AND SETTINGS

1. Be sure the POWER switch is off before

making connections.

controls fully down

(counterclockwise) for now.

2. Turn the GAIN

Set the AMP MODE

switch accordingly.

7. In STEREO mode, connect line-level cables

3. Set both LOW CUT FILTER

controls to

from your signal source to the M•1200/

their TYPICAL marks (35Hz).

M•1400’s INPUT

jacks, either XLR or

TRS:

4. Set both CONSTANT DIRECTIVITY

switches OFF (unless you’re using constant

directivity horns with compression drivers).

• The XLR and TRS inputs for each

channel are wired in parallel.

5. Set the LIMITER switch on.

• The balanced XLR inputs are wired

pin 2 = hot (+), pin 3 = cold (–) and

pin 1 = shield (ground).

Note: If you’re using the M•1200/M•1400 to

power a subwoofer, you probably do not need

an external crossover. Please see for details.

FULL SYMMETRY DUAL DIFFERENTIAL HIGH CURRENT DESIGN

PROFESSIONAL POWER AMPLIFIER

GAIN/dB

–3

INTERNAL STATUS

–6

–9

–6

–9

PROTECT

SHORT

–20

OFF

TEMP STATUS

1& 2

COLD

HOT

1.23v (+4dBu)

SENSITIVITY

SIG

POWER

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• The 1/4" TRS inputs are wired

tip = hot (+), ring = cold (–) and

sleeve = shield (ground), and can accept

either balanced (TRS) or unbalanced (TS)

cables.

15. Slowly turn both GAIN

controls up:

You should hear the music and see the SIG

and meter LEDs flashing. If the

topmost LEDs (named OL, for OverLoad)

are flashing, turn down either the GAIN

controls on the amp or the source signal’s

output level controls (i.e., master faders).

The point is: The OL LEDs should never

light up.

8. In MONO and BRIDGE modes, connect an

input cable to CHANNEL 1’s INPUT only,

and nothing into CHANNEL 2’s INPUT

(You could plug into CHANNEL 2’s input,

it just won’t do anything.)

16. For quieter listening, it is preferable to

adjust the amp’s GAIN controls rather

than the source signal’s output level

(unless you have the source’s control all

the way up!).

9. In STEREO and MONO modes, connect

speaker cables to the SPEAKER OUTPUTS

, either binding post or 1/4" TS for the

M•1200, or binding post or Speakon^®for

the M•1400:

17. Start dancing, but don’t let the ants out of

• The binding post connectors are wired

red = hot (+) and black = cold (–).

• The 1/4" TS connectors are wired

tip = hot (+) and sleeve = cold (–).

your pants.

Things You Must Remember:

• Never plug amplifier

outputs into anything

except speakers (unless

you have an outboard box

specifically designed to

handle speaker-level

signals).

10. In BRIDGE mode, connect the binding post

cable like this: the hot (+) side goes in the

CHANNEL 1 SPEAKER OUTPUTS

red

post and the cold (–) side goes in CHAN-

NEL 2’s red post. Plug nothing into the

black posts, 1/4" TS jacks, or Speakon jacks.

•

Before making connections to an amp or

reconfiguring an amp’s routing, turn the

amp’s level (GAIN) controls down, turn

the power off, make the changes, turn

the power back on, and then turn the

level controls back up.

11. Connect the other ends of the speaker

cables to your loudspeakers.

12. Plug the amp’s power cord into a

3-prong AC outlet capable of delivering at

least 15 amps.

•

If you shut down your equipment, turn

off the amplifiers first. When powering

up, turn on the amplifiers last.

Save the shipping boxes! You may need

them someday, and you probably don’t

want to have to pay for them again.

13. Make sure your signal source (the cables

feeding the M•1200/M•1400’s inputs)

is powered up and delivering signal to

the amp.

14. Turn the M•1200/M•1400’s POWER

switch on and verify that the signal present

(

SIG) LEDs are blinking.

/ BRIDGE / MONO

CAUTION

WARNING:

O R

T TO RAIN OR MOI

E P S I SI E. R

E T

E RI

K OF FI

E. DO N

VICI G TO Q

E OR E

RIC S

E C

LIFI D P

K, DO N

N L.

SERIAL NUMBER

MANUFACTURING DATE

CHANNEL

AMP MODE

MONO

CHANNEL

E THIS E UI

T R

LOW CUT

INPUT

LOW CUT

AVIS:^RRI

E DE C RI E —

TILISE UN F SIB

R A

E P S O RI

E DE R

T DE R

RISK OF ELECTRIC SHOCK

DO NOT OPEN

O U

R S

STEREO

TYPICAL

BRIDGE

FILTER

BALANCED

UNBALANCED

E WITH T

E S

E T

PE F

E A

D R

TING.

E DE M

E T

PE.

TYPICAL

35 Hz

TYPICAL

35 Hz

DIS

T S PPLY C

D B

E C

GING F

R LE F

SIB

UNBALANCED

(MONO BRIDGE)

1200 WATTS

STAGE

MONITOR

100 Hz

OHM LOAD MIN.

600 WATTS CH

MONO

BRIDGE

CONCEIVED, DESIGNED, AND MANUFACTURED

BY MACKIE DESIGNS INC • WOODINVILLE • WA

98072 • USA • MADE IN USA • PATENTS PENDING

100 Hz

OUTPUT APPLICATION

OHMS LOAD MIN.

–

OFF

170 Hz

OFF

170 Hz

FULL

SUB

RANGE

WOOFER

LIMITER (CH1

CH2)

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5 kHz

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5k Hz

FREQUENCY

–

STEREO

TYPICAL

125Hz

–

2k Hz

5.6k Hz

AIR EQ

2k Hz

5.6k Hz

120 VAC 50/60 Hz

1500 WATTS

ON OFF

63Hz

AIR EQ

OFF

TYPICAL

OFF

TYPICAL

THRU

SPEAKER OUTPUTS

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HOWTOUSETHISMANUAL

APPLICATION DIAGRAMS

THE GLOSSARY: A HAVEN OF NON-

TECHINESS FOR THE NEOPHYTE

Mackie’s gang of illustrators have created

easy-to-understand diagrams of popular studio

Just in case you’re new to the audio world,

and live-sound setups. Your setup will probably we’ve included a fairly comprehensive dictio-

be different in some way, but these diagrams nary of pro audio terms. If terms like “clipping,”

will help you see the big picture so you can add “noise floor,” or “unbalanced” leave you blank,

your own finishing touches.

flip to the glossary at the back of this manual

for a quick explanation.

FEATURE DESCRIPTIONS: MIND

BOGGLING DETAILS

A PLUG FOR THE CONNECTORS

SECTION

Each and every knob, switch, and connector

on the M•1200/M•1400 Power Amplifiers is

explained in depth here. Throughout this sec-

tion you’ll find illustrations, with each feature

numbered like this . If you’re curious about

a feature, simply locate it on the appropriate

illustration, note the number attached to it,

and find that number in the nearby paragraphs.

Also at the back of this manual is a section

on connectors: XLR, TRS, Binding Post and

Speakon connectors, balanced connectors,

unbalanced connectors, and special hybrid

connectors. If you plan on wiring your own

cables, please visit this section before you start.

ARCANE MYSTERIES ILLUMINATED

Almost last but not least, we’ve included

an appendix entitled Arcane Mysteries Illumi-

nated. This section discusses some of the down

’n’ dirty practical realities of signal transmission,

balancing a sound system, grounding, and bal-

anced versus unbalanced lines. It’s a gold mine

for the neophyte and even the seasoned pro

might learn a thing or two.

This icon marks information that is criti-

cally important or unique to the M•1200/

M•1400. For your own good, read them and re-

member them. We may call you someday and

quiz you.

TECHNICAL INFO

This section is for you tech-heads who like

to use a calculator and read specifications.

You’ll find it all here.

This icon leads you to in-depth explanations

of features and practical tips. While not man-

datory, they’ll have some valuable information.

GENERAL PRECAUTIONS AND

CONSIDERATIONS

This section discusses important things to

keep in mind when installing and using the

M•1200/M•1400, including rack mounting, AC

power, and wiring.

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CONTENTS

QUICK START .......................................................... 4

APPLICATION DIAGRAMS ......................................... 8

FEATURE DESCRIPTIONS .............................................. 11

GAIN ............................................................. 11

METERS ......................................................... 12

SIG ............................................................... 13

PROTECT........................................................ 13

SHORT........................................................... 13

TEMP STATUS ................................................. 14

POWER ......................................................... 14

POWER CORD ................................................ 15

SPEAKER OUTPUTS ......................................... 15

INPUT ........................................................... 16

THRU ............................................................ 18

LOW CUT FILTER ............................................. 18

CONSTANT DIRECTIVITY .................................. 18

CD FREQUENCY ........................................ 19

AMP MODE .................................................... 19

STEREO ................................................... 20

MONO .................................................... 20

BRIDGE ................................................... 20

OUTPUT APPLICATION ..................................... 20

LIMITER................................................... 20

SUBWOOFER ............................................ 21

FREQUENCY ............................................. 21

GENERAL PRECAUTIONS AND CONSIDERATIONS............. 23

RACK MOUNTING ........................................... 23

THERMAL CONSIDERATIONS ............................ 23

AC POWER CONSIDERATIONS........................... 23

INPUT WIRING ............................................... 24

OUTPUT WIRING ............................................ 24

70V DISTRIBUTION SYSTEMS ........................... 25

APPENDIX A: Service Info ............................................ 26

TROUBLESHOOTING ............................................. 26

REPAIR ............................................................... 27

APPENDIX B: Glossary................................................. 28

APPENDIX C: Connectors .............................................. 33

APPENDIX D: Arcane Mysteries Illuminated .................... 35

Balanced Lines ...................................................... 35

“Do’s” and “Don’ts” of Fixed Installations ............... 35

Grounding............................................................ 36

Optimizing Sound System Levels ............................. 36

Biamplified and Triamplified Systems ....................... 38

APPENDIX E: Technical Info ........................................... 39

DO THE MATH: OHMS, LOADS AND SUCH................ 39

SPECIFICATIONS ................................................... 40

BLOCK DIAGRAM ................................................. 42

COLOPHON ................................................................ 43

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APPLICATIONDIAGRAMS

OMXING

X2OUT

OMXING

X1OUT

XGCSEMAINOUTL/R

TWO M•1200S: MAIN SPEAKERS AND STAGE MONITORS

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FROM MIXING CONSOLE

MAIN OUT

FROM MIXING CONSOLE

MONITOR OUT

TYPICAL 35Hz

STEREO/TYPICAL

STAGE MONITOR 100Hz

/ BRIDGE / MONO

CAUTION

WARNING:

O R

T TO RAIN OR MOI

E P S I E. R

E T

E RI

K OF FI

E. DO N

VICI G TO Q

E OR E

RIC S

E C

LIFI D P

K, DO N

N L.

SERIAL NUMBER

MANUFACTURING DATE

CHANNEL

AMP MODE

MONO

CHANNEL

E THIS E UI

T R

LOW CUT

INPUT

LOW CUT

AVIS:^RRI

E DE C RI E —

TILI E UN F SI E DE R

R A T DE R

E P S O RI

RISK OF ELECTRIC SHOCK

DO NOT OPEN

O U

R S

STEREO

TYPICAL

BRIDGE

FILTER

BALANCED

UNBALANCED

E WI

H T

E S

E T

E F

E A

D R

E DE M

E T

TYPICAL

35 Hz

TYPICAL

35 Hz

T S

Y C

D B

E C

GI G F

R LE F

UNBALANCED

(MONO BRIDGE)

1400 WATTS

STAGE

MONITOR

100 Hz

OHM LOAD MIN.

700 WATTS CH

MONO

BRIDGE

CONCEIVED, DESIGNED, AND MANUFACTURED

BY MACKIE DESIGNS INC WOODINVILLE WA

98072 USA MADE IN USA PATENTS PENDING

100 Hz

OUTPUT APPLICATION

OHMS LOAD MIN.

–

•

OFF

170 Hz

OFF

170 Hz

FULL

SUB

RANGE

WOOFER

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5 kHz

LIMITER (CH1

CH2)

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5k Hz

FREQUENCY

–

STEREO

TYPICAL

125Hz

–

2k Hz

5.6k Hz

AIR EQ

2k Hz

5.6k Hz

AIR EQ

120 VAC 50/60 Hz

1500 WATTS

ON OFF

63Hz

OFF

TYPICAL

OFF

TYPICAL

THRU

SPEAKER OUTPUTS

CD OFF

LIMITER ON

CD OFF

M•1400: MAIN SPEAKERS AND STAGE MONITORS WITH ONE AMPLIFIER

* SEE NOTE BELOW

FROM MIXING CONSOLE

MONITOR OUT

STAGE MONITOR 100Hz

MONO MODE

STAGE MONITOR 100Hz

/ BRIDGE / MONO

CAUTION

WARNING:

O R

T TO RAIN OR MOI

E P S I E. R

E T

E RI

K OF FI

E. DO N

VICI G TO Q

E OR E

RIC S

E C

LIFI D P

K, DO N

N L.

SERIAL NUMBER

MANUFACTURING DATE

CHANNEL

AMP MODE

CHANNEL

E THIS E UI

T R

LOW CUT

INPUT

LOW CUT

AVIS:^RRI

E DE C RI E —

TILI E UN F SI E DE R

R A T DE R

E P S O RI

RISK OF ELECTRIC SHOCK

DO NOT OPEN

O U

R S

STEREO

TYPICAL

MONO

BRIDGE

FILTER

BALANCED

UNBALANCED

E WI

H T

E S

E T

E F

E A

D R

E DE M

E T

TYPICAL

35 Hz

TYPICAL

35 Hz

T S

Y C

D B

E C

GI G F

R LE F

UNBALANCED

(MONO BRIDGE)

1400 WATTS

STAGE

MONITOR

OHM LOAD MIN.

700 WATTS CH

MONO

BRIDGE

CONCEIVED, DESIGNED, AND MANUFACTURED

BY MACKIE DESIGNS INC WOODINVILLE WA

98072 USA MADE IN USA PATENTS PENDING

100 Hz

OUTPUT APPLICATION

100 Hz

OHMS LOAD MIN.

–

•

OFF

170 Hz

OFF

170 Hz

FULL

SUB

RANGE

WOOFER

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5 kHz

LIMITER (CH1

CH2)

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5k Hz

FREQUENCY

–

STEREO

TYPICAL

125Hz

–

2k Hz

5.6k Hz

AIR EQ

2k Hz

5.6k Hz

AIR EQ

120 VAC 50/60 Hz

1500 WATTS

ON OFF

63Hz

OFF

TYPICAL

OFF

TYPICAL

THRU

SPEAKER OUTPUTS

* NOTE: TOTAL IMPEDANCE MUST BE GREATER

THAN 2 OHMS PER CHANNEL

CD OFF

LIMITER ON

CD OFF

M•1400: EIGHT MONITOR SPEAKERS

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FROM ACTIVE CROSSOVER: HIGH-FREQUENCY L/R

STEREO/TYPICAL

CONSTANT DIRECTIVITY HORNS

170Hz

/ BRIDGE / MONO

CAUTION

WARNING:

E THIS E UI

E T

AIN OR MOI

S I E. R

E RI

F FI

E. D

VICI

E OR E

K, D

SERIAL NUMBER

MANUFACTURING DATE

CHANNEL

AMP MODE

MONO

CHANNEL

T T

T R

E C

LOW CUT

INPUT

LOW CUT

AVIS:^RRI

E DE C

RI E —

E UN F SI

R A

E P S O

E DE R

T DE R

RISK OF ELECTRIC SHOCK

DO NOT OPEN

R S

E PA

R S

LIFI

NEL.

STEREO

TYPICAL

BRIDGE

FILTER

BALANCED

UNBALANCED

E WI

H T

E S

E T

E F

E A

D R

TILI

E DE M

E T

TYPICAL

35 Hz

TYPICAL

35 Hz

T S

Y C

D B

E C

GI G F

ER LE F

UNBALANCED

(MONO BRIDGE)

1200 WATTS

STAGE

MONITOR

100 Hz

OHM LOAD MIN.

600 WATTS CH

MONO

BRIDGE

CONCEIVED, DESIGNED, AND MANUFACTURED

BY MACKIE DESIGNS INC WOODINVILLE WA

98072 USA MADE IN USA PATENTS PENDING

100 Hz

OUTPUT APPLICATION

OHMS LOAD MIN.

–

•

OFF

170 Hz

OFF

170 Hz

FULL

SUB

RANGE

WOOFER

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5 kHz

LIMITER (CH1

CH2)

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5k Hz

FREQUENCY

–

STEREO

TYPICAL

125Hz

–

2k Hz

5.6k Hz

AIR EQ

63Hz

2k Hz

5.6k Hz

AIR EQ

120 VAC 50/60 Hz

1500 WATTS

ON OFF

OFF

TYPICAL

OFF

TYPICAL

SPEAKER OUTPUTS

THRU

LIMITER ON

*3.5KHz CD ON

CD ON *3.5KHz

FROM ACTIVE CROSSOVER: LOW-FREQUENCY L/R

LOW-FREQUENCY

CABINETS

TYPICAL 35Hz

STEREO/TYPICAL

TYPICAL 35Hz

/ BRIDGE / MONO

CAUTION

WARNING:

E THIS E UI

E T

AIN OR MOI

S I E. R

E RI

F FI

E. D

VICI

E OR E

K, D

SERIAL NUMBER

MANUFACTURING DATE

CHANNEL

AMP MODE

CHANNEL

T T

T R

E C

LOW CUT

INPUT

LOW CUT

AVIS:^RRI

E DE C

RI E —

E UN F SI

R A

E P S O

E DE R

T DE R

RISK OF ELECTRIC SHOCK

DO NOT OPEN

R S

E PA

R S

LIFI

NEL.

STEREO

TYPICAL

MONO

BRIDGE

FILTER

BALANCED

UNBALANCED

E WI

H T

E S

E T

E F

E A

D R

TILI

E DE M

E T

TYPICAL

35 Hz

TYPICAL

35 Hz

T S

Y C

D B

E C

GI G F

ER LE F

UNBALANCED

(MONO BRIDGE)

1400 WATTS

STAGE

MONITOR

100 Hz

OHM LOAD MIN.

700 WATTS CH

MONO

BRIDGE

CONCEIVED, DESIGNED, AND MANUFACTURED

BY MACKIE DESIGNS INC WOODINVILLE WA

98072 USA MADE IN USA PATENTS PENDING

100 Hz

OUTPUT APPLICATION

OHMS LOAD MIN.

–

•

OFF

170 Hz

OFF

170 Hz

FULL

SUB

RANGE

WOOFER

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5 kHz

LIMITER (CH1

CH2)

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5k Hz

FREQUENCY

–

STEREO

TYPICAL

125Hz

–

2k Hz

5.6k Hz

AIR EQ

63Hz

2k Hz

5.6k Hz

AIR EQ

120 VAC 50/60 Hz

1500 WATTS

ON OFF

OFF

TYPICAL

OFF

TYPICAL

SPEAKER OUTPUTS

THRU

* CD HORN EQ FREQUENCY SETTING DEPENDS

ON COMPRESSION DRIVER/CD HORN COMBINATION

CD OFF

LIMITER ON

CD OFF

M•1200/ M•1400: STEREO SYSTEM WITH CD HORNS

FROM MIXING CONSOLE MAIN OUT L/R

FULL

RANGE

130Hz

STEREO/TYPICAL

130Hz

/ BRIDGE / MONO

CAUTION

WARNING:

E THIS E UI

E T

AIN OR MOI

S I E. R

E RI

F FI

E. D

VICI

E OR E

K, D

SERIAL NUMBER

MANUFACTURING DATE

CHANNEL

AMP MODE

CHANNEL

T T

T R

E C

LOW CUT

INPUT

LOW CUT

AVIS:^RRI

E DE C

RI E —

E UN F SI

R A

E P S O

E DE R

T DE R

RISK OF ELECTRIC SHOCK

DO NOT OPEN

R S

E PA

R S

LIFI

NEL.

STEREO

TYPICAL

MONO

BRIDGE

FILTER

BALANCED

UNBALANCED

E WI

H T

E S

E T

E F

E A

D R

TILI

E DE M

E T

TYPICAL

35 Hz

TYPICAL

35 Hz

T S

Y C

D B

E C

GI G F

ER LE F

UNBALANCED

(MONO BRIDGE)

1200 WATTS

STAGE

MONITOR

100 Hz

OHM LOAD MIN.

600 WATTS CH

MONO

BRIDGE

CONCEIVED, DESIGNED, AND MANUFACTURED

BY MACKIE DESIGNS INC WOODINVILLE WA

98072 USA MADE IN USA PATENTS PENDING

100 Hz

OUTPUT APPLICATION

OHMS LOAD MIN.

–

•

OFF

170 Hz

OFF

170 Hz

FULL

SUB

RANGE

WOOFER

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5 kHz

LIMITER (CH1

CH2)

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5k Hz

FREQUENCY

–

STEREO

TYPICAL

125Hz

–

2k Hz

5.6k Hz

AIR EQ

63Hz

2k Hz

5.6k Hz

AIR EQ

120 VAC 50/60 Hz

1500 WATTS

ON OFF

OFF

TYPICAL

OFF

TYPICAL

SPEAKER OUTPUTS

THRU

CD OFF

LIMITER ON

CD OFF

SUBWOOFERS

20Hz

BRIDGE MODE

20Hz

/ BRIDGE / MONO

CAUTION

WARNING:

E THIS E UI

E T

AIN OR MOI

S I E. R

E RI

F FI

E. D

VICI

E OR E

K, D

SERIAL NUMBER

MANUFACTURING DATE

CHANNEL

AMP MODE

CHANNEL

T T

T R

E C

LOW CUT

INPUT

LOW CUT

AVIS:^RRI

E DE C

RI E —

E UN F SI

R A

E P S O

E DE R

T DE R

RISK OF ELECTRIC SHOCK

DO NOT OPEN

R S

E PA

R S

LIFI

NEL.

STEREO

TYPICAL

MONO

BRIDGE

FILTER

BALANCED

UNBALANCED

E WI

H T

E S

E T

E F

E A

D R

TILI

E DE M

E T

TYPICAL

35 Hz

TYPICAL

35 Hz

T S

Y C

D B

E C

GI G F

ER LE F

UNBALANCED

(MONO BRIDGE)

1400 WATTS

STAGE

MONITOR

100 Hz

OHM LOAD MIN.

700 WATTS CH

MONO

BRIDGE

CONCEIVED, DESIGNED, AND MANUFACTURED

BY MACKIE DESIGNS INC WOODINVILLE WA

98072 USA MADE IN USA PATENTS PENDING

100 Hz

OUTPUT APPLICATION

OHMS LOAD MIN.

–

•

OFF

170 Hz

OFF

170 Hz

FULL

SUB

RANGE

WOOFER

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5 kHz

LIMITER (CH1

CH2)

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5k Hz

FREQUENCY

–

STEREO

TYPICAL

125Hz

–

2k Hz

5.6k Hz

AIR EQ

63Hz

2k Hz

5.6k Hz

AIR EQ

120 VAC 50/60 Hz

1500 WATTS

ON OFF

OFF

TYPICAL

OFF

TYPICAL

SPEAKER OUTPUTS

THRU

SUBWOOFER MODE

@ 125Hz

CD OFF

M•1200/ M•1400: STEREO SYSTEM WITH BRIDGED SUBWOOFER

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FEATUREDESCRIPTIONS

GAIN

Constant Gain vs. Constant Sensitivity

There are two viewpoints, or philosophies,

regarding the gain structure of power amplifi-

ers — constant gain and constant sensitivity.

Constant gain means that regardless of the

output power of the amplifier, the gain from in-

put to output remains the same. (By the way,

this refers to the full gain of the amplifier, with

the gain or level controls all the way up.)

Within a product line of constant gain power

amplifiers, as the output power rating of an

amplifier increases, the level of the input volt-

age must also increase.

For example, if an amplifier is rated at

100W into an 8-ohm load, and it has 26 dB of

gain, it requires an input signal of 1.4V rms to

drive it to full power. This is about +5 dBu, a

reasonable operating point for professional

gear.

These giant knobs control the levels to the

output section of the M•1200/M•1400 amplifi-

ers. You’ll notice that their travel is detented,

meaning there are 40 built-in “resting points”

so you can easily set both controls to the same

level. Usually, these controls are set all the

way up.

The gain structure of the amplifier is de-

signed so that a +4 dBu (1.23V rms) input

signal drives the amplifier to full rated power

into 4 ohms (40V rms @ 4 ohms = 400 watts for

the M•1200). This is how the sensitivity

of an amplifier is defined. In this case, it

equates to a voltage gain of about 30 dB (okay,

30.24 dB for those of you sittin’ there with your

calculator!).

The graphics around the knob depict two

different methods for setting the gain. The in-

ner circle is marked in dB, calibrated from off

(∞) to 30. This represents the amount of volt-

age gain from input to output. When using

professional equipment with +4 dBu output

levels, set the GAIN control all the way up to 30.

The outer circle is labeled in volts, with in-

dications of 1V, 2V, and 3V. These correspond to

the input sensitivity of the amplifier. With the

GAIN control all the way up (fully clockwise),

the input sensitivity is 1.23V, which works well

with professional equipment operating at a

nominal +4 dBu level.

On the other hand, you may want your lis-

tening level to be quieter than the M•1200/

M•1400’s maximum level. For instance, if

you’re using the M•1200/M•1400 as a control

room amp, and your control room is the size of

a telephone booth, you’ll probably never want

to hear the amp at its maximum level.

Now take an amplifier rated at 200W into an

8-ohm load. If it also has a gain of 26 dB, it re-

quires an input signal of 2.0V rms to drive it to

full power, or +8 dBu.

This can become problematic as the power

of the amplifier increases. What if you have a

power amp rated at 800W into 8 ohms? This

will require an input signal of 4.0V rms to drive

it to full power. This equates to a whopping

+14.3 dBu!! You’ve just robbed your mixer of

10 dB of headroom. You’ll either have to have a

good limiter to keep the transient peaks down,

or turn down the level from the mixer and not

use all the power available from the amplifier.

Constant sensitivity means that regardless

of the output power of the amplifier, the input

sensitivity of the amplifier (the input voltage

required to attain full output power) remains

the same. As the output power of an amplifier

increases, the gain of the amplifier must also

increase.

Referring back to the previous example, an

amplifier rated at 100W into 8 ohms with a

gain of 26 dB requires an input signal of 1.4V

rms to drive it to full power. It has an input

sensitivity of 1.4V rms. In order for the 200W

amplifier to reach full power into 8 ohms with

a 1.4V rms input signal, it must have a gain of

29 dB. And the 800W amplifier will require a

gain of 35 dB to reach full power with a 1.4V

You can set the GAIN con-

trols as low as you like.

However, reducing the

GAIN controls requires an

increased input level to

reach full power at the amplifier’s output.

See the sidebar “Constant Gain vs. Constant

Sensitivity” for a better understanding of how

this works.

Like all amplifier controls, you’ll typically

determine the optimal settings during installa-

input signal.

Continued on page 12

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tion or sound check, then leave them alone,

using your signal source (usually a mixer) to

control listening levels as you work. Or play.

So what are the pros and cons of these two

approaches? The reason some amplifier

manufacturers use the constant gain ap-

proach is because the noise specification

looks better. It’s a fact of physics that as the

gain of the amplifier increases, the circuit

noise is amplified and increases too. By main-

taining a constant gain, the noise spec for an

800W amplifier can look as good as the noise

spec for a 100W amplifier. The downside to

this is that you have to crank up your mixer

level feeding the input of the amplifier, losing

headroom and possibly increasing the noise

level from the mixer (unless you have a

Mackie mixer with low-noise VLZ circuitry!).

Conversely, constant sensitivity demands

that as the power increases, so must the gain.

Yes, the output noise of the amplifier will

increase, but you maintain the critical head-

room available from your mixer. The addition-

al noise is generally not a problem in live

sound reinforcement situations. If it is, you

can turn down the GAIN control a few clicks

to find a happy compromise between noise

floor and headroom available (see “Optimiz-

ing Sound System Levels” in Appendix D).

As an added benefit, you can drive multiple

amplifiers with the same signal and get the

maximum power available from all of them.

Mackie subscribes to the philosophy of

constant sensitivity. Our amplifiers can be

driven to full power with an input level of

+4 dBu (1.23V rms).

You may wonder why we

didn’t use just one stereo

control to control both sides.

That’s in case your applica-

tion requires a left/right

imbalance (due to an irregularly shaped room)

or if you’re using the two sides for completely

different purposes (monitor in channel 1 and

side-fill in channel 2, for instance). Besides,

they look cool.

METERS

The M•1200/M•1400’s meters indicate the

relative output level of the amplifier refer-

enced to full power. The numbers next to the

meter’s LEDs are in dB below full power.

Ideally, the M•1200/M•1400’s –20 –9,

–6, and –3 LEDs will flicker at normal signal

levels, while the OL LED may flicker occasion-

ally during peak moments.

OL is short for Overload. Overloading, or

clipping, occurs when the output voltage no

longer linearly follows the input voltage and

simply stops. This causes a sine wave to

“square off,” or get “clipped off.” Thus, the term

clipping. Fear not — this scenario is quite un-

likely. Even with the GAIN controls fully up,

the M•1200/M•1400 amplifiers easily accept

professional “+4 dBu” operating levels.

FULL SYMMETRY DUAL DIFFERENTIAL HIGH CURRENT DESIGN

GAIN/dB

–3

INTERNAL STATUS

–6

–9

–6

–9

PROTECT

SHORT

–20

TEMP STATUS

1& 2

COLD

HOT

1.23v (+4dBu)

SENSITIVITY

SIG

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If the OL (Overload) LED

is blinking frequently or

continuously, turn down

the source signal (i.e. the

mixer’s master faders).

The M•1200/M•1400

amps draw their ventila-

tion air in from the front

and out through the side

panels. The amp needs

plenty of fresh air to stay cool. DO NOT BLOCK

THE VENTILATION PORTS. See “Thermal

SIG

SIG (short for “signal present”) is the lowest Considerations”

step in the meters’ ladder. It senses the signal

prior to the GAIN control, so when SIG is lit,

SHORT

you know the M•1200/M•1400 is receiving signal.

If this LED comes on, the M•1200 or

If it’s the only meter LED lit (meaning the other M•1400 has detected a short circuit in either

meter LEDs are not lit), the M•1200/M•1400 is of the outputs, meaning that the hot (+) and

receiving a very weak signal (below –20 dB).

cold (–) speaker wires are touching, or a

speaker itself is shorted out. Such a condition

causes the M•1200/M•1400 to engage its

PROTECT

If the PROTECT LEDs are on, the M•1200/

M•1400’s output section has shut down. That,

of course, means you won’t hear anything until

you rectify the situation. Three things can

cause the PROTECT circuit to engage:

1. Powering up the M•1200/M•1400. A built-

in delay circuit saves your speakers (and

ears) from the thumps or pops that can

sometimes occur when powering up a

system. During this 3 second delay, the

PROTECT LEDs light up.

PROTECT

mode (when a signal is present),

muting all signals at the amp’s outputs.

This short-circuit LED is a Mackie exclusive

(until the other guys “borrow” the idea) and

can save precious minutes of your trouble-

shooting time. Without it, you’d still have

speaker and amp protection (via the PROTECT

circuit), but you wouldn’t be able to determine

the source of the problem. But with the SHORT

LED, the M•1200/M•1400 comes right out and

tells you!

WARNING: The SHORT LEDs indicate an

unsafe condition for the power amplifier. Once

the SHORT LED is lit, you must turn the power

off, wait for the indicator to extinguish, and

turn the power back on again to reset the am-

plifier.

2. A short circuit (or near short) in either of

the outputs. Both the PROTECT and the

SHORT

LEDs light up.

3. The temperature in the M•1200/M•1400

has risen to an unsafe level. The PROTECT

and the TEMP STATUS LEDs

light up.

Typical causes for a “short” indication would

be either a shorted speaker cable or too many

speaker cabinets connected to the amplifier

(i.e., the load impedance is too low). If a “short”

is indicated, please check your cables. If the

cabling is OK, then reduce the number of cabi-

nets driven by the amplifier.

PROFESSIONAL POWER AMPLIFIER

OFF

POWER

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Note: When using the amplifier in BRIDGE

mode, one or both SHORT LEDs may light

under shorted or low impedance conditions.

Regardless of whether one or both LEDs light,

it’s an indication of a problem that requires

further investigation.

constant temperature gradient cooling tunnel

to remove additional heat from the output

transistors. However, if the internal tempera-

ture of the amplifier should exceed 80°C

(176°F), the COLD LED turns off, the HOT

LED turns on, and both PROTECT LEDs shine.

The output of the amplifier is muted — at this

point the amplifier is in Standby mode and

remains there until the internal temperature

cools off to a safe level (55°C or 131°F). When

this occurs, the HOT LED and PROTECT LEDs

turn off, the COLD LED turns on and normal

operation resumes.

TEMP STATUS

TEMP (short for temperature) is another

feature designed to keep your mind at ease.

Normally the COLD LED is lit, indicating that

the M•1200/M•1400 is working normally.

Under extreme conditions the amplifier may

overheat. You may ask, “What kind of extreme

conditions?”

Overheating problems are usually caused by

one of the following situations: improper venti-

lation, high ambient temperatures, overdriving

the amplifier into clipping, driving the ampli-

fier hard into low impedance loads, frayed or

partially shorted speaker cables, or defective

or internally shorted speakers.

Be Aware: If the HOT LED

comes on frequently, some-

thing is overworking the

M•1200/M•1400 or it’s not

properly ventilated. Look

at each of the “extreme conditions” described

above and try to determine what is causing the

amplifier to overheat. Refer to the “Trouble-

shooting” section in Appendix A for more help.

The heaviest load the M•1200/M•1400 can

tolerate is 2 ohms per channel (4 ohms in

bridged mode). If you’ve got a set of speakers

wired in parallel, be sure the load isn’t adding

up to less than 2 ohms. Anything below 2 ohms

What’s that? Why doesn’t the

fan just go fast all the time?

Well, if it did, you might actu-

can cause the SHORT

LED to light and trig-

ally hear it whirring during

ger the PROTECT mode.

your quiet moments (there

are quiet moments in your life, aren’t there?).

Remember: As the load gets While this whirring would be of no concern in

“heavier,” its value in ohms

goes down. For instance, a

2-ohm speaker load is twice

most live-sound situations, it could become

annoying in a control room environment. So,

when the M•1200/M•1400 is not working hard,

the fan goes slow; when the music gets loud

and puts the amp to work, the fan goes fast.

as “heavy” as a 4-ohm load.

Please see “Do The Math: Ohms, Loads and

Such” in Appendix E to learn about speaker

loads.

POWER

As the internal temperature of the amplifier

To make the amp operate, push the top half

rises, the fan kicks into high speed. This occurs of the POWER switch. It clicks into place and a

at 60°C (140°F). More air moves through the

SERIAL NUMBER

MANUFACTURING DATE

CAUTION

WARNING: TO RED

CE THE RISK OF FIRE OR ELECTRIC SH

EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE. DO NOT REM VE C

NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL.

K, DO NOT

VER.

RISK OF ELECTRIC SHOCK

DO NOT OPEN

AVIS:RISCQUE DE C

LECTRIQUE — NE PAS O VRIR

REPLACE WITH THE SAME TYPE FUSE AND RATING.

DISCONNECT SUPPLY CORD BEFORE CHANGING FUSE

UTILISE UN FUSIBLE DE RECHANGE DE MÊME TYPE.

DEBRANCHER AVANT DE REMPLACER LE FUSIBLE

(MONO BRIDGE)

1200 WATTS

4 OHM LOAD MIN.

600 WATTS CH

2 OHMS LOAD MIN.

MONO

BRIDGE

CONCEIVED, DESIGNED, AND MANUFACTURED

BY MACKIE DESIGNS INC • WOODINVILLE • WA

98072 • USA • MADE IN USA • PATENTS PENDING

–

120 VAC 50/60 Hz

1500 WATTS

SPEAKER OUTPUTS

M•1200 Rear Panel

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soothing green light adjacent to it glows. To

turn the amp off, push the lower half. It’ll click

again and the green light will extinguish.

When you power up the M•1200/M•1400,

a built-in delay circuit prevents any pops or

thumps from being transmitted to the speakers

due to turn-on instability in the system. Be sure

the signal driving the amplifier is turned

down when you first power up the system.

There are few things as rude as 3 seconds of

silence followed by 225 watts of full-blast

stereo sound! (Well, maybe 225 kilowatts of

accordian music...)

SPEAKER OUTPUTS

Some call them “GR” jacks, others call them

“Banana” jacks, but we prefer to call them

“Binding Posts.” You can call them whatever

you like (except late for supper). These termi-

nals are your standard fare.

To use the binding post outputs, you can

terminate your speaker cables with single or

double banana plugs, spade lugs, or leave them

unterminated: Unscrew the amp’s binding

posts enough to reveal the holes on their sides,

then insert your stripped wires (stripped about

3/8" back) into the holes and retighten the

posts (finger tight is fine — please don’t reef

on them with a wrench!). Be careful that no

runaway strands touch the chassis or other

terminals.

The red posts are labeled “+,” which means

positive. The black posts are labeled “–” for

negative. You probably know the importance of

getting these terms correct — if one side is

hooked up “in phase” and the other side is “out

of phase,” you’ll be “out of work.” (By the way,

although everyone says “phase” in this situa-

tion, the correct word is “polarity”... but it’s not

as much fun to say.)

If you shut down your

system, turn off your ampli-

fiers first. When powering

up, turn on your amplifiers

last. This way, equipment

feeding the amp won’t “pop” or “thud” when it’s

powered up or down.

POWER CORD

We all know what a power cord is. The

M•1200 and M•1400 have big beefy cords built

in. Plug the power cord into a 3-prong outlet

that is capable of delivering 120VAC at 15 amps.

Using high-quality stranded speaker cable

(16 gauge or thicker), connect the positive

outputs of the M•1200/M•1400 to the positive

inputs of your speakers, and the negative out-

puts to the negative inputs. The exception: If

you’re using the M•1200/M•1400 in BRIDGE

mode, this does not apply. Please read on.

Note (M•1200 only): In addition to the

binding posts, the M•1200 also has 1/4" TS

(tip-sleeve) SPEAKER OUTPUTS, so you can

use speaker cables with 1/4" TS plugs. The tip

is positive (+) and the shield is negative (–).

They’re wired in parallel with the binding posts

and behave exactly the same (except they

For current-delivery

purposes, the M•1200/

M•1400’s voltage source

(wall outlet, extension

cords, or power strips)

must be capable of continuously delivering 15

amps. And for safety reasons, that source must

be a “3-prong” outlet with hot, neutral, and

ground terminals. We’re dealing with some big-

time electricity here — don’t mess with it. See

“AC Power Considerations”

can’t be used in BRIDGE

mode).

/ BRIDGE / MONO

CHANNEL

AMP MODE

LOW CUT

INPUT

STEREO

TYPICAL

MONO

BRIDGE

FILTER

BALANCED

UNBALANCED

TYPICAL

35 Hz

TYPICAL

35 Hz

UNBALANCED

STAGE

MONITOR

100 Hz

OUTPUT APPLICATION

OFF

170 Hz

OFF

170 Hz

FULL

SUB

RANGE

WOOFER

LIMITER (CH1 & CH2)

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5 kHz

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5k Hz

FREQUENCY

STEREO

TYPICAL

125Hz

2k Hz

5.6k Hz

AIR EQ

ON OFF

63Hz

AIR EQ

OFF

TYPICAL

OFF

TYPICAL

AIR EQ

THRU

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In fact, you can use both the 1/4" jacks and

the binding posts simultaneously. Just remem- in direct contact), you don’t want the speaker

ber that doing so creates two parallel loads. ends of live cables to zap every piece of equip-

Please see “Do The Math: Ohms, Loads and Such” ment they touch as they’re being dragged

and “shorts” (positive and negative signal lines

in Appendix E to learn about speaker loads.

across the stage.

Be Aware: Should you

choose to terminate your

speaker cables with the

1/4" TS plugs, make sure

nobody confuses these

Ordinarily, applying a posi-

tive voltage to a speaker’s

positive input and negative

voltage to the negative input

results in an outward excur-

cables with line-level cables, (i.e., guitar

cables). Guitar cords are not designed to

handle the high current output of power am-

plifiers. And line-level inputs (like the signal

input on a mixer) are not designed to handle

speaker-level voltages.

If you’re using low impedance loads at high

power levels, we recommend that you use the

binding post speaker outputs rather than the

1/4" TS jacks. Although 1/4" jacks are conve-

nient and easy to use, they were not designed

to handle high-level currents.

Note (M•1400 only): In addition to the

binding posts, the M•1400 also has Speakon^®

connectors for connecting the speakers to the

amplifier. These are locking connectors that

are easy to attach and are designed to handle

high power levels into low-impedance loads.

Pin 1+ is positive (+) and Pin 1– is negative (–).

sion of the woofer. But some woofers are built

with reverse polarity, meaning that the above

conditions result in an inward excursion.

If you’re not sure which type of speakers you

have, take a look at their literature. If you’re

still not sure, here is a simple test: take a 1.5V

flashlight battery and connect the positive

terminal of the battery to the positive (+) in-

put of the speaker, and connect the negative

terminal of the battery to the negative (–) in-

put of the speaker. Observe the motion of the

speaker cone. It should move out when voltage

is applied, and return to rest when voltage is

removed. Make sure all the speakers in the

system move in the same direction (there are a

few exceptions — some speakers are deliber-

ately designed with reverse-polarity woofers).

INPUT

The M•1200/M•1400 amplifiers give you a

Before making connections choice — they have the traditional XLR inputs,

to an amp or reconfiguring as well as 1/4" TRS (tip-ring-sleeve) input jacks.

an amp’s signal routing,

turn the amp’s GAIN

Sonically (and electrically) they’re identical,

so choose either one. Since these two inputs

controls down, turn the

are in parallel (the THRU

jacks are in

POWER

off, make the changes, turn the

parallel with the inputs as well), you shouldn’t

POWER back on, and then turn the GAIN con- connect more than one source to the SIGNAL

trols back up. Although the M•1200/M•1400 INPUT jacks. Each can be used with either

amplifiers can handle “opens” (no connection) balanced or unbalanced signals.

SERIAL NUMBER

MANUFACTURING DATE

CAUTION

WARNING: TO RED

CE THE RISK OF FIRE OR ELECTRIC SH

EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE. DO NOT REM VE C

NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL.

K, DO NOT

VER.

RISK OF ELECTRIC SHOCK

DO NOT OPEN

AVIS:RISCQUE DE C

LECTRIQUE — NE PAS O VRIR

REPLACE WITH THE SAME TYPE FUSE AND RATING.

DISCONNECT SUPPLY CORD BEFORE CHANGING FUSE

UTILISE UN FUSIBLE DE RECHANGE DE MÊME TYPE.

DEBRANCHER AVANT DE REMPLACER LE FUSIBLE

(MONO BRIDGE)

1400 WATTS

4 OHM LOAD MIN.

700 WATTS CH

2 OHMS LOAD MIN.

MONO

BRIDGE

CONCEIVED, DESIGNED, AND MANUFACTURED

BY MACKIE DESIGNS INC • WOODINVILLE • WA

98072 • USA • MADE IN USA • PATENTS PENDING

–

120 VAC 50/60 Hz

1500 WATTS

SPEAKER OUTPUTS

M•1400 Rear Panel

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When connecting a balanced signal using

the XLR or 1/4" jacks, they’re wired thusly, per

AES (Audio Engineering Society) standards:

Unbalanced TS (tip-sleeve) lines can be ac-

commodated via the TRS jack. Make sure the

cord terminates with a TS plug (like a guitar

plug), or if it’s a TRS plug (like a headphone

plug), make sure the ring is tied to the shield,

preferably at the source.

XLR

Pin 2

Pin 3

TRS

Tip

Ring

Shield

Hot (+)

Cold (–)

Shield (Ground) Pin 1

SLEEVE

TIP

SHIELD

RING (COLD)

TIP (HOT)

HOT

SLEEVE (SHIELD)

COLD

Unbalanced 1/4" TS plug

SHIELD

You can connect an unbalanced XLR cable

to the M•1200/M•1400, although this would be

unusual — as unusual as an unbalanced XLR

output. However, if you have an unbalanced

XLR connection to make, refer to the “Connec-

tors” section (Appendix C) at the back of this

manual for more information.

COLD

HOT

SHIELD

COLD

HOT

Balanced XLR Connectors

The M•1200/M•1400 amps expect to see

a nominal signal level anywhere between the

–10dBV “semipro” and +4 dBu “pro” standards,

meaning almost any line-level mixer or other

device can be plugged into the amp’s INPUTs.

RING SLEEVE

TIP

SLEEVE RING TIP

RING (COLD)

TIP (HOT)

Use the GAIN

controls to adjust the gain of

SLEEVE (SHIELD)

the amplifier to match the signal level you’re using.

Balanced ¹⁄4" TRS Plugs

If you set the AMP MODE

switch in MONO or

BRIDGE, use the CHAN-

NEL 1 inputs only — the

CHANNEL 2 inputs are

disabled in this case.

/ BRIDGE / MONO

CHANNEL

AMP MODE

LOW CUT

INPUT

STEREO

TYPICAL

MONO

BRIDGE

FILTER

BALANCED

UNBALANCED

TYPICAL

35 Hz

TYPICAL

35 Hz

UNBALANCED

STAGE

MONITOR

100 Hz

OUTPUT APPLICATION

OFF

170 Hz

OFF

170 Hz

FULL

SUB

RANGE

WOOFER

LIMITER (CH1 & CH2)

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5 kHz

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5k Hz

FREQUENCY

STEREO

TYPICAL

125Hz

2k Hz

5.6k Hz

AIR EQ

ON OFF

63Hz

AIR EQ

OFF

TYPICAL

OFF

TYPICAL

AIR EQ

THRU

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THRU

can’t reproduce — you can’t hear it, and worse

yet, it’s a waste of amplifier power that can be

better used reproducing frequencies you can hear.

Someday you’ll do a show at Carnegie Hall

and realize that one M•1200 or M•1400 ampli-

fier is just not going to do the job — you’ll need

a six-foot-high rack full of ’em. That’s what the

THRU jack is for. Simply plug the signal source

5dB

–5dB

outputs into the first amp’s INPUT

, patch

–10dB

–15dB

from that amp’s THRU jacks to the next amp’s

INPUTs, and so on, daisy-chaining as many

amps as you can afford (assuming your console

has low-impedance outputs).

1Hz

100

10k

20k

Low Cut Filter Frequency Response

In order to match the output bandwidth

with your particular speaker system, the

M•1200/M•1400 amplifier has a tunable LOW

CUT FILTER. The frequencies are clearly

marked along the knob’s travel

A general rule of thumb is to

maintain a load impedance

10 times or more than the

source impedance to prevent

excessive loading. If your

•

Fully counterclockwise, the frequency is

below 10Hz, effectively bypassing the filter.

Center detent is 35Hz and labeled TYPICAL

since precious few woofers actually go

below that.

console has an output impedance of 100 ohms,

then you can daisy-chain up to twenty M•1200/

M•1400 amplifiers, which presents a load of

1000 ohms to the console (input impedance of

20 kohms divided by 20 amplifiers = 1000 ohms).

The THRU jacks can also be used to relay

the signal on to other devices such as a DAT or

cassette recorder, enabling you to record ex-

actly what the audience is hearing. The THRU

jacks are wired straight from the XLR and TRS

•

3/4 of the way up is labeled STAGE MONI-

TOR, 100Hz, perfect for, well, stage monitors

(they seldom reproduce below 100Hz;

besides, it prevents low-frequency “leak-

age” into the house).

Fully clockwise is labeled 170Hz

INPUT

— there is no electronic circuitry

So, grab your woofer’s spec sheet and find

between — so the signal going into the amp is

exactly the same as the signal coming out of

the THRU jacks.

the low roll-off spec. Then set the M•1200/

M•1400’s LOW CUT FILTER at the same

frequency.

If you do this correctly (and make sure the

You can use the THRU jack

as an input, if necessary,

since it’s wired in parallel

with the other input connec-

tors. You can also use the

meters

are happy), you’ll never again see

your woofer moving sporadically without au-

dible signal. Your system will play louder and

cleaner, and you may never blow another

woofer again!

1/4" TRS INPUT jacks as THRU jacks. Simply

connect the 1/4" TRS INPUT jacks on the first

amplifier to the TRS 1/4" INPUT jacks on the

second amplifier using 3-conductor shielded

cables with TRS plugs on both ends.

Warning: If you use a regular guitar cord with

2-conductor TS plugs, you’ll unbalance the sig-

nal at the XLR input by grounding the low side

(–) of the signal (pin 3).

CONSTANT DIRECTIVITY

Compression drivers mounted on constant-

directivity horns require compensation, in the

form of a high-frequency boost, with its “knee”

set somewhere between 2.5kHz and 6kHz.

Until now, you’d have to resort to external

crossovers or worse yet, graphic EQ modules.

Both of these are fraught with limitations, not

to mention adding cost, rack space require-

ments and complexity to your system.

LOW CUT FILTER

Every woofer has frequency response speci-

fications. It’s usually expressed in Hertz (or

cycles per second), like “40Hz–300Hz.” The

“40Hz” refers to the low-frequency point (usu-

ally, but not always) where the speaker’s

output drops by 3 dB, and will "roll off" com-

pletely as the frequency goes down. There is no

point in sending a woofer any frequencies it

The M•1200/M•1400 Power Amplifiers

eliminate the need for any of these external

devices — they have the compensation cir-

cuitry already built in. And using it is a breeze.

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CD Frequency

More on Constant Directivity Horns

Back in the early ’70s, radial

Your compression drivers’ spec sheet should

have a suggested frequency for compensation

boost. If so, just turn the CONSTANT DIREC-

TIVITY switch ON and set its knob to match

that frequency. If your spec sheet doesn’t have

that information, you can simply adjust the

Frequency knob by ear, preferably using the

same music as the actual performance (3.5kHz

is a good place to start).

horns were the common

mechanism for reproducing

high frequencies. Radial

horns had a serious problem,

though. The high frequencies

tended to beam straight ahead, so if you moved

away from front and center (off-axis), the bril-

liance and sizzle quickly diminished to a

muffled blur. Constant Directivity horns were

designed to spread the higher frequencies

evenly throughout the horn’s dispersion pattern.

This was accomplished by using a smaller

opening to the horn, using straight sidewalls in

both the horizontal and vertical planes (radial

horns typically have curved vertical sections

that cause beaming), and providing a flare at

the mouth of the horn to disperse the mid to

high frequencies.

15dB

10dB

5dB

–5dB

100

1kHz

10kHz 20kHz

Constant Directivity EQ

Wait, there’s more: If you don’t have con-

stant directivity horns, you can forget all this,

and leave the switch OFF

All high-frequency compression drivers have

an inherent roll-off of about 6 dB per octave

above about 3kHz. The exact frequency at

which the roll-off occurs (called the mass

Or, better yet, you can use this CONSTANT

DIRECTIVITY feature to enhance your EQ

curve. By setting the Frequency knob fully

clockwise, you introduce a very high frequency breakpoint) depends on the materials used,

boost to the signal (above 6kHz). And in

the mass of the moving parts (diaphragm and

voice coil) and the strength of the magnet. The

CONSTANT DIRECTIVITY HORN EQ control

on the M•1200/M•1400 compensates for this

natural roll-off in the power response of the

compression driver coupled to a CD horn, with

the end result of flat-frequency response (con-

stant) with a wide coverage angle (directivity).

Mackie-land, this gentle boost has a name: AIR

as seen on our SR series of consoles. By boost-

ing these high frequencies, AIR will breathe

life into your mix, making cymbals brighter

and vocals silkier.

Speaking of Mackie SR consoles: If you use

both the AIR feature on an SR console as well

as the AIR feature just described on the

M•1200/M•1400, you may be overdoing it. You

won’t hyperventilate or anything, but it might

cause your audience to experience ear fatigue

from too much high-frequency content. Too

much of a good thing, perhaps.

AMP MODE

This three-way switch, along with the OUT-

PUT APPLICATION’s

three-way switch,

determines what kind of amplifier you want

the M•1200/M•1400 to be.

/ BRIDGE / MONO

CHANNEL

AMP MODE

LOW CUT

INPUT

STEREO

TYPICAL

MONO

BRIDGE

FILTER

BALANCED

UNBALANCED

TYPICAL

35 Hz

TYPICAL

35 Hz

UNBALANCED

STAGE

MONITOR

100 Hz

OUTPUT APPLICATION

OFF

170 Hz

OFF

170 Hz

FULL

SUB

RANGE

WOOFER

LIMITER (CH1 & CH2)

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5 kHz

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5k Hz

FREQUENCY

STEREO

TYPICAL

125Hz

2k Hz

5.6k Hz

AIR EQ

ON OFF

63Hz

AIR EQ

OFF

TYPICAL

OFF

TYPICAL

AIR EQ

THRU

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The AMP MODE switch determines the in-

To use all the M•1200/M•1400’s power to

put signal routing within the M•1200/M•1400

drive one speaker cabinet using BRIDGE mode,

amplifier. Shipped from the factory, the switch you’ll have to do four things:

is set to STEREO. This is correct for about 90% 1. Turn off the power to the M•1200/M•1400.

of the applications using an amp like this

(hence the TYPICAL indicator near it). But

you may be in the 10% bracket, requiring spe-

cial input routing within the amp.

AMP MODE should be configured before

operation — if you must change it during per-

2. Set the AMP MODE

switch to BRIDGE.

3. Connect the positive side of the speaker

cable to the Channel 1 red (+) binding post.

4. Connect the negative side of the speaker

cable to the Channel 2 red (+) binding post.

5. (Okay, make that five things!) Use only the

formance, turn down the GAIN

controls as

CHANNEL 1 INPUT

the SUBWOOFER OUTPUT APPLICATION).

(unless you’re using

a precaution to protect the speakers from any

inadvertent pops or thumps.

The CHANNEL 1 GAIN control adjusts the

output level of the amplifier. The CHANNEL 2

GAIN control has no effect.

STEREO

mode (separate left and right

inputs, separate left and right outputs) is the

typical setup for amplifying stereo signals.

Once again: Before making connections to

an amp or reconfiguring an amp’s routing, turn

the power off, make the changes, then turn the

power back on.

MONO

mode (sometimes called Dual-

Mono – one mono input, two mono outputs) is

for sending a mono signal to two different

speaker sets, with separately-adjustable GAIN

controls.

OUTPUT APPLICATION

BRIDGE

mode (sometimes called

The OUTPUT APPLICATION switch should

be configured before you turn on the amplifier.

This switch allows you to choose between three

different configurations:

LIMITER ON (TYPICAL). This is the normal

configuration: full-bandwidth audio with pro-

tective limiting (please see ).

Bridged-Mono – one mono input, one mono

output) uses both sides of the amp to double

the power to one speaker set. With two M•1200

power amplifiers, each set to BRIDGE mode,

you can deliver as much as 1200 watts per

amplifier.

LIMITER OFF is also full bandwidth audio,

but without protective limiting (please see ).

SUBWOOFER mode, with built-in low-pass

filter, no protective limiting (please see ).

If you set the AMP MODE

switch in MONO or

BRIDGE, use the CHAN-

NEL 1 inputs only — the

CHANNEL 2 inputs go no-

where in this case.

LIMITER

The LIMITER is not designed to alter your

sound — it’s just there to protect your speak-

ers from clipping. Its effect is virtually

Note: There is one exception to this rule. If you

have the OUTPUT APPLICATION switched to

SUBWOOFER, the inputs to Channels 1 and 2

are summed regardless of the AMP MODE

setting (see ). Also, BRIDGE mode re-

quires special connections at the SPEAKER

transparent, meaning you probably won’t even

notice any audible difference. We recommend

that you leave it engaged (via OUTPUT APPLI-

CATION ), hence the TYPICAL label below it.

If you’re working at quiet levels all the time,

or you’ve already placed a compressor/limiter

in the signal path, or if you just hate compres-

sion, you can leave the LIMITER out of the

circuit (via OUTPUT APPLICATION ).

OUTPUTS

BRIDGE

In STEREO mode, the M•1200 Power

Amplifier can deliver 600 watts per side into

2 ohms. If that’s not enough, you can use two

M•1200s, each in BRIDGE mode, and deliver

1200 watts per amplifier into 4 ohms. The

M•1400 produces 630 watts per side into

2 ohms in STEREO and 1260 watts into 4 ohms

in BRIDGE mode. Or, you can use one amp in

BRIDGE mode to power a monaural system.

Finally, BRIDGE mode is also popular for

subwoofer applications — but please see

The LIMITER senses when

the amp is about to be

overdriven and attenuates

the overall level just enough

to keep the signal from clip-

ping. Clipping occurs when the output voltage

no longer linearly follows the input voltage

and simply stops. This causes a sine wave to

SUBWOOFER

for a special subwoofer surprise.

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“square off,” and the average power going into

the speaker is roughly double that of a sine

wave. Square waves sound awful, and could

possibly damage your speakers and/or your

reputation.

Since most low-frequency energy is mono-

phonic (the same in both channels), the

subwoofer circuit takes the signal from both

Channels 1 and 2 and sums them together. This

summed signal is then directed to both power

amplifier output stages. It doesn’t matter

The LIMITER is especially handy when

you’re working with loud output levels. Having whether the AMP MODE

switch is set to

the signal spikes (kick drum, for instance) at- STEREO, MONO, or BRIDGE, it will sum the

tenuated a bit can actually increase the

apparent loudness of the overall mix without

diminishing the “power” behind the spikes.

inputs when the OUTPUT APPLICATION

switch is set to SUBWOOFER

Here’s how to configure it:

1. Turn the M•1200/M•1400’s POWER

off.

Be Forewarned: With the

LIMITER engaged, you can

still overdrive the amplifier

into clipping. It just takes a

stronger signal to do it. So

2. Set the OUTPUT APPLICATION

switch

to SUBWOOFER

3. Select a rolloff point, via the FREQUENCY

switch: At “125Hz,” you’ll get the low

sub-harmonics on up to the audible bass

range. At “63Hz,” you’ll get just the lowest

frequencies, more to be felt than heard.

You’ll probably want to try this switch both

ways.

even with the LIMITER turned on, you should

still pay attention to the OL LEDs

SUBWOOFER

4. Connect your cords and speaker cables as

Here’s a special surprise: If you bought the

M•1200/M•1400 amplifier to power a subwoofer

system, you just saved yourself the cost of a

crossover! The M•1200/M•1400 amps have an

active SUBWOOFER filter built in. You can use

it, along with the variable LOW CUT FILTER

in a second M•1200/M•1400, to reproduce the

function of a crossover.

usual (see “Quick Start” ). Set the AMP

MODE

to either STEREO, MONO, or

BRIDGE, depending on your application.

STEREO and MONO operate the same

(

with SUBWOOFER activated).

5. Turn the M•1200/M•1400’s POWER on.

Woof!

If you want to use a second M•1200/M•1400

to reproduce the rest of the audio range, follow

this procedure:

5dB

–5dB

1. Connect the THRU

jacks on the first

–10dB

–15dB

subwoofer amplifier to the INPUT

on the second amplifier.

2. With POWER off, set the OUTPUT

jacks

100

1kHz

10kHz

20kHz

Subwoofer Filter

APPLICATION

switch on the second

amplifier to FULL RANGE

ON or OFF).

(

LIMITER either

/ BRIDGE / MONO

CHANNEL

AMP MODE

LOW CUT

INPUT

STEREO

TYPICAL

MONO

BRIDGE

FILTER

BALANCED

UNBALANCED

TYPICAL

35 Hz

TYPICAL

35 Hz

UNBALANCED

STAGE

MONITOR

100 Hz

OUTPUT APPLICATION

OFF

170 Hz

OFF

170 Hz

FULL

SUB

RANGE

WOOFER

LIMITER (CH1 & CH2)

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5 kHz

CONSTANT DIRECTIVITY

HORN EQ /AIR EQ

4.5k Hz

FREQUENCY

STEREO

TYPICAL

125Hz

2k Hz

5.6k Hz

AIR EQ

ON OFF

63Hz

AIR EQ

OFF

TYPICAL

OFF

TYPICAL

AIR EQ

THRU

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3. Set the LOW CUT FILTER

frequency

2. Adjust the signal generator level so you

measure 1V rms output at 1kHz. (You

should turn down the GAIN knobs on the

amplifier about halfway.)

control to either 63Hz or 125Hz, depending

on the cutoff frequency selected in the

subwoofer amplifier

Since these exact frequencies are not la-

beled on the amplifier, you can guesstimate the

position of the knob. 63Hz is located at about

1 o’clock and 125Hz is about 4 o’clock.

If you want to be really accurate, you will

need to use a variable-frequency signal genera-

tor along with a frequency counter and a volt-

meter or oscilloscope to find the exact position

for the knob. The voltmeter or o’scope should

be capable of measuring low frequencies accu-

rately (down to 60Hz).

3. Change the frequency of the signal genera-

tor to 63Hz or 125Hz, whichever you’re

using as your subwoofer crossover fre-

quency. You may need to use a frequency

counter for accuracy.

4. Adjust the LOW CUT FILTER

frequency

control until the voltmeter or o’scope reads

0.707VAC rms. This is the –3 dB point, and

means you have now matched the LOW

CUT FILTER frequency cut-off point to the

SUBWOOFER FREQUENCY switch setting

(either 63Hz or 125Hz).

1. Connect the signal generator to the INPUT

of the amplifier and monitor the

After you’ve completed this exercise, you

should mark the position of the control with

a stick-on arrow or label so you don’t have

to repeat it should the control accidentally

get moved.

SPEAKER OUTPUT

with the voltmeter

or o’scope.

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GENERALPRECAUTIONSANDCONSIDERATIONS

RACK MOUNTING

AC POWER CONSIDERATIONS

The M•1200/M•1400 amp requires two rack

Be sure the M•1200/M•1400 is plugged into

space units (2U = 3.5"). It also requires 16.25" an outlet that is able to supply 120VAC at high

depth inside the rack, including the rear sup-

ports. When designing your rack, put the

heavier items at the bottom and the lighter

items toward the top.

Secure the front panel of the amplifier to

the front of the rack using four screws with soft

current. If the voltage should drop below

116VAC, the M•1200/M•1400 will no longer be

able to supply rated power. (It will continue to

operate down to 50% of the rated voltage, but it

just won’t be able to reach full rated power.)

Be sure the AC outlet can supply enough

washers to prevent scratching the panel. In ad- current to allow full power operation of all the

dition, because of the weight of the amplifier,

you must secure the rear support brackets of

amplifiers plugged into it. The outlet should be

a three-prong socket that matches the power

the amplifier to the back of the rack. You could cord.

use a support rail or shelf across the back of

the rack, or angle brackets attached between

the rear support brackets and the rear rails of

the rack. This is recommended for all compo-

nents mounted in a rack that is going to be

moved frequently (or thrown in the back of a

pickup truck and transported down a bumpy

gravel road to that outdoor festival!).

WARNING: Bypassing the plug’s ground pin

can be dangerous. Please don’t do it.

The AC current demand of an amplifier var-

ies depending on several factors, including the

crest factor and the duty cycle of the program

material. Under typical conditions reproducing

rock music where musical peaks are just below

clipping, the M•1200/M•1400 will require the

following average currents:

THERMAL CONSIDERATIONS

Average

Current

Required

3.2A

Peak

Current

Required

25A

The M•1200/M•1400 amps are fan-cooled

and bring air in through the front and out

through the sides. Make sure that cool air is

available at the front of the amplifier, and that

there is room on each side for the warm air to

exit from the amplifier and dissipate. If rack-

mounted, make sure there is room for the

warm air to circulate around the side and out

through the rear of the rack. In a typical rack,

there will be a space of 1 to 2 inches on either

side of the amplifier. This is adequate to allow

the warm air to exit from the amplifier.

Amplifier Loading

2 ohms per side or 4 ohms bridged

4 ohms per side or 8 ohms bridged

8 ohms per side or 16 ohms bridged

16A

10A

It is recommended that a stiff supply of AC

power be used because the amplifier places

high current demands on the AC line. The

more power that is available on the line, the

louder the amplifier will play and the more

peak output power will be available for cleaner,

punchier bass.

The M•1200/M•1400’s unique T-Design

Constant Gradient Cooling Tunnel provides

substantially better cooling for the output tran-

sistors than conventional designs that simply

blow air through the chassis, getting dust and

other contaminants over all the internal

components. The Cooling Tunnel provides a

shorter, more directed path so the cool air con-

centrates on the heat produced by the output

devices. This results in increased reliability

and longevity for the amplifier.

Having said this, we also realize that in

many applications a standard 15A service may

be all that is available. Under typical condi-

tions, reproducing rock music where musical

peaks are just below the clipping point, you

can safely connect more than one amplifier to

a 15A service. Use the table below as a guide-

line:

Maximum Number

of Amplifiers

Amplifier Loading

on a 15A Service

2 ohms per side or 4 ohms bridged

4 ohms per side or 8 ohms bridged

8 ohms per side or 16 ohms bridged

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The extension cord used to supply power to to a common (“star”) grounding point, and the

the “amp rack” should have a third wire safety distance between the outlets and the common

ground to avoid presenting a safety hazard. We grounding point should be as short as possible.

also recommend using a cord that has conduc-

If lighting is used in a show, it is preferable

tors large enough to avoid severely limiting the to power the lights from one leg of the service,

amplifier’s ability to supply high currents on

transients. With this in mind, we recommend

and power the audio equipment from the other

leg. This will help minimize noise from the

using the following for a fully loaded 15A service: lights coupling into the audio (particularly if

SCRs are used).

Extension Cord Length Wire Gauge

When setting up for a show, oftentimes you

are plugging into an AC power distribution sys-

tem you know nothing about. You may even be

faced with 2-wire outlets that are missing the

third safety ground pin. It’s a good idea to have

a three-wire AC outlet tester in your toolbox so

25 feet

50 feet

100 feet

14 AWG

12 AWG

10 AWG

Power amplifiers can have

momentary peak current re- you can check the outlets yourself to make

quirements many times

above the nominal average

current draw. According to

sure they are wired correctly. These testers will

tell you if the polarity of the hot and neutral

wires is reversed and if the safety ground is dis-

connected. Don’t use an outlet if it is wired

Ohm’s Law, the greater the resistance of the

linecord, the more input power is lost between improperly! This is to protect yourself as well

the AC outlet and the power amplifier (across

the linecord). And to further aggravate the

matter, this relationship is nonlinear. The

amount of power lost across the linecord in-

creases exponentially as the current demand

increases. So if the current demand doubles

momentarily because of an exceptionally loud

bass note, the amount of AC input power lost

across the linecord increases four times. You

can see that it is very important to keep the

resistance of the linecord to a minimum. That’s

why we recommend using a heavy gauge exten-

sion cord (like 14 gauge or bigger). Remember,

wire gets thicker as the gauge number gets

smaller (10 gauge is thicker than 14 gauge).

as your equipment.

If you find that you must plug into a two-

wire outlet, you will need to use a two-wire to

three-wire adapter (cheater plug). These come

with a metal tab that you put underneath the

center screw that holds the AC outlet faceplate

in place. This center screw should be grounded.

You can check it by connecting the adapter to

the outlet and then plugging in your AC outlet

tester.

INPUT WIRING

Use a high-quality 3-conductor shielded

cable to connect the signal between the signal

source (mixing console, equalizer, etc.) and

the balanced inputs to the amplifier. If you’re

using the unbalanced inputs, use a high-quality

2-conductor shielded cable. Your Mackie

Dealer can recommend a suitable cable for

your application.

AC Power Distribution

The majority of AC outlets encountered in

homes and clubs are served by a 240VAC cen-

ter-tapped service entrance transformer. This

provides two phases of AC power on either side

of the center tap at 120V each.

If you want to build your own cables, refer to

the “Connectors” section in Appendix C.

In order to minimize ground loops, the safety

grounds for all the outlets should be connected

OUTPUT WIRING

Use heavy gauge, stranded wire for connect-

ing speakers to the M•1200/M•1400 amplifier’s

HIGH VOLTAGE POWER LINE

SPEAKER OUTPUT

terminals. As the dis-

tance between the amplifier and the speakers

increases, the thickness of the wire should also

increase. Speaker wire has resistance, and

when electricity passes through a resistor,

power is lost. The thicker the wire, the less re-

sistance it offers, and the more power actually

gets to the speakers.

120V

PRIMARY

WINDING

SECONDARY

WINDING

240V

120V

EARTH

GROUND

(NEUTRAL)

TRANSFORMER

240V Center-Tapped Secondary

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The thickness of wire is rated in gauges.

Use the chart below to determine the correct

gauge of wire to use according to the distance

between the speakers and the amplifier, and

tions when setting up a multi-speaker system.

You just add up the total wattages of all the

speakers in the system and make sure that it

doesn’t exceed the total power rating of the

the impedance of the load the amplifier is driv- amplifier (allowing at least 10% for insertion

ing. This ensures that the power lost across the losses). Another benefit is that by using high

speaker wire is less than 0.5 dB.

voltage and low current, losses in the speaker

distribution wiring are kept to a minimum.

Standard voltage levels include 25V, 70V, and

100V, but 70V systems are most commonly used

in commercial sound distribution systems in

the U.S.

Because of the high power capability of the

M•1200/M•1400 amplifiers, they can be used

to directly drive 70V constant-voltage distribu-

tion systems without the use of a step-up

transformer. When the M•1200 amplifier is

Load

Gauge of

Wire

Wire Length

Up to 25 ft.

Impedance

2Ω

14 gauge

16 gauge

18 gauge

12 gauge

14 gauge

18 gauge

10 gauge

12 gauge

16 gauge

8 gauge

10 gauge

14 gauge

6 gauge

8 gauge

12 gauge

4 gauge

6 gauge

10 gauge

4Ω

8Ω

Up to 40 ft.

Up to 60 ft.

Up to 100 ft.

Up to 150 ft.

Up to 250 ft.

2Ω

4Ω

8Ω

2Ω

operated in BRIDGE

mode, it can produce

4Ω

800 watts into 8 ohms, or 80V. This is slightly

higher than the standard 70.7V for which the

system was designed. You can recalculate the

actual power delivered to each tap by multiply-

ing the tap’s rated wattage by a correction

8Ω

2Ω

4Ω

8Ω

2Ω

factor (K). The correction factor is P¹/P2

4Ω

where P¹is the power delivered by the amplifier

into 8 ohms (BRIDGE mode), and P2 is the

power delivered by 70.7V into 8 ohms (625W).

M•1200: K = 800W/625W = 1.28. Thus, a

2.5W tap becomes 3.2W, a 5W tap becomes

6.4W and a 10W tap becomes 12.8W.

M•1400: K = 850W/625W = 1.32. Thus, a

2.5W tap becomes 3.3W, a 5W tap becomes

6.6W and a 10 W tap becomes 13.2W.

CAUTION: A characteristic oftapped transform-

ers is that they saturate at very low frequencies,

which causes their impedance to decrease, ap-

proaching the DC resistance of the copper wire.

This can result in overloading the amplifier if

the signal contains lots of low frequencies.

When using an FR Series amplifier in a 70V dis-

tribution system, set the LOW CUT FILTER

to 100Hz or higher. In addition, install an RC

8Ω

2Ω

4Ω

8Ω

70V DISTRIBUTION SYSTEMS

A distributed sound system uses a constant-

voltage, high-impedance network that feeds a

number of tapped transformers which, in turn,

deliver power to individual speakers. Each tap

is rated in watts, so you can select the amount

of power delivered to the speaker. Developed

for distributed paging and public address sys-

tems, one benefit of such a system is that it

eliminates complicated impedance calcula-

FR SERIES

POWER AMPLIFIER

network at the SPEAKER OUTPUT

of the

IN BRIDGE MODE

RC NETWORK

C1 C2

amplifier, as shown in the figure below.

CH 1

–

70V LINE

–

CH 2

CONSTANT

VOLTAGE

TRANSFORMER

RC NETWORK VALUES

C1 = C2 = 660µF @ 250VDC

R1 = 4Ω @ 100W

ALTERNATE RC NETWORK

Note: You can substitute

a single capacitor for C1/C2.

C3 = 330µF @ 250VDC,

NON-POLARIZED.

POWER TAP

SWITCH

–

70V Constant Voltage

Distribution System

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APPENDIXA:ServiceInfo

WARRANTY SERVICE

•

If the OUTPUT APPLICATION

set to SUBWOOFER , make sure the

frequency control is

set to OFF or nearly OFF. If it is turned up

above the subwoofer cutoff frequency, then

there will be no output from the amplifier.

switch is

Details concerning Warranty Service are

spelled out on the Warranty Card included with

your amplifier (if it’s missing, let us know and

we’ll rush one to you).

LOW CUT FILTER

If you think your amplifier has a problem,

please do everything you can to confirm it be-

fore calling for service, including reading

through the following Troubleshooting section.

Doing so might save you from the deprivation

of your amplifier and the associated suffering.

Of all Mackie products returned for service

(which is hardly any at all), roughly 50% are

coded “CND” — Could Not Duplicate, which

usually means the problem lay somewhere else

in the system. These may sound obvious to you,

but here are some things you can check:

•

Is the SHORT

LED lit? Turn the POWER

off, check the speaker connections and

make sure that there are no strands of wire

shorting across the speaker terminals.

Is the HOT TEMP STATUS

LED lit?

Make sure there is cool air available at the

front of the amplifier. Make sure there is

room at the sides of the amplifier for warm

air to exit. Allow the amplifier to cool off.

Are there fuses in the speaker or in-line

fuses in the speaker wire? Check ’em to see

if they’re blown.

•

Make sure the speakers are working

properly.

TROUBLESHOOTING

No power!

One side is way louder than the other!

•

Our favorite question: Is it plugged in?

Make sure the AC outlet is live (check with

a tester or lamp).

•

Do the M•1200/M•1400’s meters

read the same on both sides? If not, your

source signal may be delivering an out-

of-balance stereo signal.

Are both GAIN

position?

Are the speaker(s) impedances

matched? (See Appendix E — “Do The

Math: Ohms, Loads and Such.”)

Try swapping sides: Turn off the amp,

swap the speaker cables at the amp, turn

the amp back on. If the same side is still

louder, the problem is with your speak-

ers or speaker cabling. If the other side

is louder now, the problem is with the

mixer, the amp, or the line-level cabling.

•

Our next favorite question: Is the POWER

switch

on? If not, try turning it on.

•

knobs set to the same

Is the green light next to the power switch

illuminated? If not, make sure the AC

outlet is live. If so, refer to “No Sound”

below.

•

The AC line fuse inside the cabinet is

blown. This is not a user-serviceable part.

Refer to “Repair” on the next page to find

out how to proceed.

•

No sound!

•

Are the GAIN

controls turned all the

way down? Slowly turn them up and see if

you hear anything.

The stereo music sounds kind of sideways,

and the bass frequencies diminish when

standing center, but get louder as you

approach one side!

•

Is the signal source turned up? Make sure

the signal level from the mixing console (or

whatever device immediately precedes the

amplifier) is high enough to produce sound

•

Check the polarity of the speaker cable

connections. You may have your positive

and negative connections reversed at

one end of one speaker cable.

in the amplifier. The SIG

LEDs should

be blinking to indicate that signal is

present.

•

If the speakers are wired for BRIDGE mode,

make sure the AMP MODE

set to BRIDGE

switch is

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As soon as the music gets loud, the amp

shuts down!

REPAIR

Service for the U.S. versions of our amplifi-

•

Check the M•1200/M•1400’s meters

Be sure that OL is not lighting up

frequently or continuously.

Can the amp breathe? The M•1200/M•1400

amps draw their ventilation air in from the

front and out through the side panels.

They need plenty of fresh air to stay cool.

Do not block the ventilation ports.

ers is available only from one of our authorized

domestic service stations or at the factory, lo-

cated in sunny Woodinville, Washington.

(Service for amplifiers living outside the

United States can be obtained through local

dealers or distributors.) If your amplifier needs

service, follow these instructions:

•

1. Review the preceding troubleshooting

suggestions. Please.

•

Is the SHORT

LED lit? If so, you’ve got

2. Call Tech Support at 1-800-258-6883, 8am

to 5pm PST, to explain the problem and

request an RA (Return Authorization)

number. Have your amplifier’s serial

a dead short somewhere in your speaker

setup, or the total impedance of the load is

too low. Turn the amp off and rectify that

right away.

number ready. You must have an RA

number before you can obtain service at

the factory or an authorized service center.

Something’s missing in the mid and high

frequencies!

3. Keep this owner’s manual. We don’t need it

to repair the amplifier.

•

If you’re using horns with compression

drivers, please read CONSTANT

DIRECTIVITY

4. Pack the amplifier in its original package,

including endcaps and box. This is very

important. When you call for the RA

number, please let Tech Support know if

you need new packaging. Mackie is not

responsible for any damage that occurs due

to non-factory packaging.

It hurts when I touch my arm, or my leg, or

even my head!

•

You have a broken finger.

Bad sound!

5. Include a legible note stating your name,

shipping address (no P.O. boxes), daytime

phone number, RA number, and a detailed

description of the problem, including how

we can duplicate it.

•

Is it loud and distorted? Turn down the

signal coming from the mixer or signal source.

Is the input connector plugged completely

into the jack? Check the speaker connec-

tions and verify that all connections are

tight and that there are no stray strands of

wire shorting across the speaker terminals.

6. Write the RA number in BIG PRINT on top

of the box.

7. Ship the amplifier to us. We recommend

United Parcel Service (UPS). We suggest

insurance for all forms of cartage. Ship to

this address:

•

If possible, listen to the signal source with

headphones plugged into the console. If it

sounds bad there, the problem’s not in the

amplifier.

Noise/ Hum

Mackie Designs

SERVICE DEPARTMENT

16220 Wood-Red Rd. NE

Woodinville, WA 98072

•

Check the signal cable between the mixer

and the amplifier. Make sure all connections

are good and sound.

Make sure the signal cable is not routed

near AC cables, power transformers, or

other EMI-inducing device.

Is there a light dimmer or other SCR-based

device on the same AC circuit as the

monitor? Use an AC line filter or plug the

amplifier into a different AC circuit.

8. We’ll try to fix the amplifier within three

business days. We normally send everything

back prepaid using UPS BLUE (Second

Day Air). However, if you rush your ampli-

fier to us by Air Shipment, we’ll treat it in

kind by letting it jump to the head of the

line, and we’ll also ship it back to you UPS

RED (Next Day Air). This paragraph does not

necessarily apply to non-warranty service.

•

If possible, listen to the signal source with

headphones plugged into the console. If it

sounds noisy there, the problem’s not in the

amplifier.

Refer to “Grounding” in Appendix D.

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APPENDIXB:Glossary

This Glossary contains brief definitions of

many of the audio and electronic terms used in

discussions of sound mixing and recording.

clipping

A cause of severe audio distortion that is the

result of excessive gain requiring the peaks of

Many of the terms have other meanings or nu- the audio signal to rise above the capabilities

ances or very rigorous technical definitions

which we have sidestepped here because we

figure you already have a lot on your mind. If

of the amplifier circuit. Seen on an oscillo-

scope, the audio peaks appear clipped off. To

avoid distortion, reduce the system gain in or

you’d like to get more information, you can call before the gain stage in which the clipping oc-

Mix Bookshelf at 1-800-233-9604. We recom-

mend the following titles: The Audio

curs. See also headroom.

Dictionary, by Glenn White; Tech Terms, by

Peterson & Oppenheimer; Handbook for

Sound Engineers, by Glen Ballou; Mackie

Mixer Book by Rudy Trubitt; and Sound Rein-

forcement Handbook, by Gary Davis.

console

A term for a sound mixer, usually a large

desk-like mixer.

crest factor

The ratio of the peak value to the RMS

value. Musical signals can have peaks many

times higher than the RMS value. The larger

the transient peaks, the larger the crest factor.

balanced

In a classic, balanced audio circuit, the two

legs of the circuit (+ and –) are isolated from

the circuit ground by exactly the same imped-

ance. Additionally, each leg may carry the signal dB

at exactly the same level but with opposite po-

larity with respect to ground. In some balanced

See decibel.

circuits, only one leg actually carries the signal, dBA

but both legs exhibit the same impedance char-

acteristics with respect to ground. Balanced

input circuits can offer excellent rejection of

common-mode noise induced into the line and

also make proper (no ground loops) system

Sound Pressure Level (SPL) measured with

an “A” weighting filter.

dBm

A unit of measurement of audio signal level

in an electrical circuit, expressed in decibels

referenced to 1 milliwatt. The “m” in dBm

stands for “milliwatt.” In a circuit with an im-

pedance of 600 ohms, this reference (0 dBm)

grounding easier. Usually terminated with ¹⁄4

TRS or XLR connectors.

bandwidth

The band of frequencies that pass through a corresponds to a signal voltage of 0.775 VRMS

device with a loss of less than 3 dB, expressed

(because 0.775 V across 600 ohms equals 1mw).

in Hertz or in musical octaves. Also see Q.

dBu

bus

A unit of measurement of audio signal level

An electrical connection common to three

in an electrical circuit, expressed in decibels

or more circuits. In mixer design, a bus usually referenced to 0.775 VRMS into any impedance.

carries signals from a number of inputs to a

mixing amplifier, just like a city bus carries

people from a number of neighborhoods to

their jobs.

Commonly used to describe signal levels within

a modern audio system.

dBv

A unit of measurement equal to the dBu but

channel

no longer in use. It was too easy to confuse a

A functional path in an audio circuit: an in- dBv with a dBV, to which it is not equivalent.

put channel, an output channel, a recording

channel, the left channel, and so on.

dBV

A unit of measurement of audio signal level

in an electrical circuit, expressed in decibels

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referenced to 1 VRMS across any impedance.

Commonly used to describe signal levels in

consumer equipment. To convert dBV to dBu,

add 2.2 dB.

EMI

Electro Magnetic Interference. This refers

to current induced into the signal path as a

result of an external magnetic field. In audio

systems, this is usually manifested as a 60Hz or

120Hz hum or buzz. The source of this noise

can be from a ground loop or from the signal

wire coming too close to a strong magnetic

decibel (dB)

The dB is a ratio of quantities measured in

similar terms using a logarithmic scale. Many

audio system parameters measure over such a field such as a transformer or high-current

large range of values that the dB is used to sim- linecord.

plify the numbers. A ratio of 1000V:1V=60 dB.

When one of the terms in the ratio is an

agreed-upon standard value such as 0.775V,

1V, or 1mw, the ratio becomes an absolute

value, i.e., +4 dBu, –10dBV, or 0 dBM.

EQ curve

A graph of the response of an equalizer, with

frequency on the x (horizontal) axis and am-

plitude (level) on the y (vertical) axis.

Equalizer types and effects are often named

after the shape of the graphed response curve,

detent

A point of slight physical resistance (a click- such as peak, dip, shelf, notch, knee, and so on.

stop) in the travel of a knob or slide control,

used in Mackie mixers to indicate unity gain.

equalization

Equalization (EQ) refers to purposefully

changing the frequency response of a circuit,

sometimes to correct for previous unequal re-

sponse (hence the term, equalization), and

more often to add or subtract level at certain

frequencies for sound enhancement, to remove

extraneous sounds, or to create completely

new and different sounds.

diffraction

The bending of sound waves around an ob-

stacle (Huygens Principle). The longer the

wavelength in comparison to the obstacle, the

more the wave will diffract around it.

dipping

The opposite of peaking, of course. A dip is

an EQ curve that looks like a valley, or a dip.

Dipping with an equalizer reduces a band of

frequencies. See guacamole.

Bass and treble controls on your stereo are

EQ; so are the units called parametrics and

graphics and notch filters.

A lot of how we refer to equalization has to

do with what a graph of the frequency response

would look like. A flat response (no EQ) is a

straight line, a peak looks like a hill, a dip is a

dry

Usually means without reverberation, or

without some other applied effect like delay or valley, a notch is a really skinny valley, and a

chorusing. Dry is not wet, i.e. totally unaf-

fected.

shelf looks like a plateau (or a shelf). The

slope is the grade of the hill on the graph.

Graphic equalizers have enough frequency

slider controls to form a graph of the EQ right

on the front panel. Parametric EQs let you vary

several EQ parameters at once. A filter is sim-

ply a form of equalizer that allows certain

frequencies through unmolested while reduc-

ing or eliminating other frequencies.

duty cycle

The ratio of pulse width to total cycle time.

dynamic

In sound work, dynamic refers to the class

of microphones that generates electrical sig-

nals by the movement of a coil in a magnetic

field. Dynamic microphones are rugged, rela-

tively inexpensive, capable of very good

performance and do not require external power.

Aside from the level controls, EQs are prob-

ably the second most powerful controls on any

mixer (no, the power switch doesn’t count!).

fader

dynamic range

Another name for an audio level control.

The range between the maximum and mini- Today, the term refers to a straight-line slide

mum sound levels that a sound system can

handle. It is usually expressed in decibels as

the difference between the level at peak clip-

ping and the level of the noise floor.

control rather than a rotary control.

filter

A simple equalizer designed to remove

certain ranges of frequencies. A low-cut filter

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(also called a high-pass filter) reduces or

eliminates frequencies below its cutoff fre-

quency. There are also high-cut (low-pass)

filters, bandpass filters (which cut both high

and low frequencies but leave a band of fre-

Maintaining a good safety ground is always

essential to prevent electrical shock. Follow

manufacturer’s suggestions and good electrical

practices to ensure a safely grounded system.

Never remove or disable the grounding pin on

quencies in the middle untouched), and notch the power cord.

filters (which remove a narrow band but leave

the high and low frequencies alone).

In computer and audio equipment, tiny

currents and voltages can cause noise in the

circuits and hamper operation. In addition to

providing safety, ground provisions in these

frequency

The number of times an event repeats itself situations serve to minimize the pickup, detec-

in a given period. Sound waves and the electri- tion and distribution of these tiny noise signals.

cal signals that represent sound waves in an

audio circuit have repetitive patterns that

range from a frequency of about 20 repetitions

This type of ground is often called technical

ground.

Quality audio equipment is designed to

per second to about 20,000 repetitions per sec- maintain a good technical ground and also op-

ond. Sound is the vibration or combination of

vibrations in this range of 20 to 20,000 repeti-

tions per second, which gives us the sensation

of pitch, harmonics, tone, and overtones. Fre-

erate safely with a good safety ground. If you

have noise in your system due to technical

grounding problems, check your manual for

wiring tips or call technical support. Never dis-

quency is measured in units called Hertz (Hz). able the safety ground to reduce noise problems.

One Hertz is one repetition or cycle per second.

ground loop

gain

The measure of how much a circuit ampli-

fies a signal. Gain may be stated as a ratio of

A ground loop occurs when the technical

ground within an audio system is connected to

the safety ground at more than one place. Two

input to output values, such as a voltage gain of or more connections will allow tiny currents to

4, or a power gain of 1.5, or it can be expressed flow in the loops created, possibly inducing

in decibels, such as a line amplifier with a gain noise (hum) in the audio system. If you have

of 10 dB.

noise in your system due to ground loops,

check your manual for wiring tips or call tech-

nical support. Never disable the safety ground

to reduce noise problems.

gain stage

An amplification point in a signal path,

within either a system or a single device. Over-

all system gain is distributed between the

various gain stages.

headroom

The difference between nominal operating

level and peak clipping in an audio system. For

example, a mixer operating with a nominal line

level of +4 dBu and a maximum output level of

+22 dBu has 18 dB of headroom. Plenty of

room for surprise peaks.

graphic EQ

A graphic equalizer uses slide pots for its

boost/cut controls, with its frequencies evenly

spaced through the audio spectrum. In a per-

fect world, a line drawn through the centers of

the control shafts would form a graph of the

frequency response curve. Get it? Or, the posi-

tions of the slide pots give a graphic

Hertz

The unit of measure for frequency of oscilla-

tion, equal to 1 cycle per second. Abbreviated

representation of boost or cut levels across the Hz. KHz (pronounced “kay-Hertz”) is an abbre-

frequency spectrum.

viation for kilohertz, or 1000 Hertz.

ground

Also called earth. Ground is defined as the

point of zero voltage in a circuit or system, the

reference point from which all other voltages

are measured. In electrical systems, ground

connections are used for safety purposes, to

keep equipment chassis and controls at zero

voltage and to provide a safe path for errant

currents. This is called a safety ground.

See Hertz.

impedance

The AC resistance/capacitance/inductance

in an electrical circuit, measured in ohms. In

audio circuits (and other AC circuits) the im-

pedance in ohms can often be very different

than the circuit resistance as measured by a

DC ohmmeter.

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Maintaining proper circuit impedance rela- formers to hear themselves. Monitor speakers

tionships is important to avoid distortion and

minimize added noise. Mackie input and out-

are also called foldback speakers. In recording,

the monitor speakers are those used by the

put impedances are designed to work well with production staff to listen to the recording as it

the vast majority of audio equipment.

progresses. In zoology, the monitor lizard is the

lizard that observes the production staff as the

recording progresses. Keep the lizard out of the

mixer.

knee

A knee is a sharp bend in an EQ response

curve not unlike the sharp bend in your leg.

Also used in describing dynamics processors.

noise

Whatever you don’t want to hear. Could be

hum, buzz, or hiss; could be crosstalk or digital

hash or your neighbor’s stereo; could be white

noise or pink noise or brown noise; or it could

be your mother-in-law reliving the day she had

her gallstone removed.

level

Another word for signal voltage, power,

strength, or volume. Audio signals are some-

times classified according to their level.

Commonly used levels are: microphone level

(–40 dBu or lower), instrument level (–20 to

–10 dBu), and line level (–10 to +30 dBu).

noise floor

The residual level of noise in any system. In

a well-designed product, the noise floor will be

a very quiet hiss, which is the thermal noise

generated by bouncing electrons in the transis-

tor junctions. The lower the noise floor and the

higher the headroom, the more usable dynamic

range a system has.

line level

A signal whose level falls between –10 dBu

and +30 dBu.

master

A control affecting the final output of a

mixer. A mixer may have several master con-

trols, which may be slide faders or rotary

controls.

parametric EQ

A “fully” parametric EQ is an extremely pow-

erful equalizer that allows smooth, continuous

control of each of the three primary EQ param-

eters (frequency, gain, and bandwidth) in each

section independently. “Semi” parametric EQs

mixer

An electronic device used to combine vari-

ous audio signals into a common output.

Different from a blender, which combines vari- allow control of fewer parameters, usually fre-

ous fruits into a common libation.

quency and gain (i.e., they have a fixed

bandwidth, but variable center frequency and

gain).

monaural

Literally, pertaining to or having the use of

only one ear. In sound work, monaural has to

do with a signal which, for purposes of commu-

peaking

The opposite of dipping, of course. A peak

nicating audio information, has been confined is an EQ curve that looks like a hill, or a peak.

to a single channel. One microphone is a mono Peaking with an equalizer amplifies a band of

pickup; many microphones mixed to one chan- frequencies.

nel is a mono mix; a mono signal played

through two speakers is still mono, since it only phone jack

carries one channel of information. Several

Ever see those old telephone switchboards

monaural sources, however, can be panned

with hundreds of jacks and patch cords and

into a stereo (or at least two-channel, if you are plugs? Those are phone jacks and plugs, now

going to be picky) mix. Monaural sound rein- widely used with musical instruments and

forcement is common for environments where audio equipment. A phone jack is the female

stereo sound reinforcement would provide an

uneven reproduction to the listener.

connector, and we use them in 1⁄4" two-con-

ductor (TS) and three-conductor (TRS)

versions.

monitor

In sound reinforcement, monitor speakers

(or monitor headphones or in-the-ear

monitors) are those speakers used by the per-

phone plug

The male counterpart to the phone jack.

See above.

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TRS

Acronym for Tip-Ring-Sleeve, a scheme for

A way of stating the bandwidth of a filter

or equalizer section. An EQ with a Q of .75 is

broad and smooth, while a Q of 10 gives a nar-

row, pointed response curve. To calculate the

connecting three conductors through a single

plug or jack. 1⁄4" phone plugs and jacks and

1⁄8" mini phone plugs and jacks are commonly

value of Q, you must know the center frequency wired TRS. Since the plug or jack can carry two

of the EQ section and the frequencies at which signals and a common ground, TRS connectors

the upper and lower skirts fall 3 dB below the

are often referred to as stereo or balanced

level of the center frequency. Q equals the cen- plugs or jacks. Another common TRS applica-

ter frequency divided by the difference between tion is for insert jacks, used for inserting an

the upper and lower –3 dB frequencies. A peak- external processor into the signal path. In

ing EQ centered at 10kHz whose –3 dB points

are 7.5kHz and 12.5kHz has a Q of 2.

Mackie mixers, the tip is send, ring is return,

and sleeve is ground.

RFI

Radio Frequency Interference. High

frequency radiation that often results from

sparking circuits. This can be manifested in a

Acronym for Tip-Sleeve, a scheme for con-

necting two conductors through a single plug

or jack. 1⁄4" phone plugs and jacks and 1⁄8"

number of ways in audio systems, but is usually mini phone plugs and jacks are commonly

evident as a high-frequency buzz or hash sound. wired TS. Sometimes called mono or unbal-

anced plugs or jacks. A 1⁄4" TS phone plug or

RMS

jack is also called a standard phone plug or

An acronym for root mean square, a conven- jack.

tional way to measure AC voltage and audio

signal voltage. Most AC voltmeters are cali-

brated to read RMS volts. Other conventions

unbalanced

An electrical circuit in which the two legs of

include average volts, peak volts, and peak-to- the circuit are not balanced with respect to

peak volts.

ground. Usually, one leg will be held at ground

potential. Unbalanced circuit connections re-

quire only two conductors (signal “hot” and

ground). Unbalanced audio circuitry is less

expensive to build but under certain circum-

stances is more susceptible to picking up noise.

shelving

A term used to describe the shape of an

equalizer’s frequency response. A shelving

equalizer’s response begins to rise (or fall) at

some frequency and continues to fall (or rise)

until it reaches the shelf frequency, at which

point the response curve flattens out and re-

mains flat to the limits of audibility. If you were

to graph the response, it would look like a

shelf. At least, more like a shelf than a hiking

boot. The EQ controls on your stereo are usu-

ally shelving equalizers. See also peaking and

dipping.

unity gain

A circuit or system that has its voltage gain

adjusted to be one, or unity. A signal will leave

a unity gain circuit at the same level at which

it entered. In Mackie mixers, unity gain is

achieved by setting all variable controls to the

marked “U” setting. Mackie mixers are opti-

mized for best headroom and noise figures at

unity gain.

stereo

volume

Believe it or not, stereo comes from a Greek

word that means solid. We use stereo or stereo-

phonic to describe the illusion of a continuous,

spacious soundfield that is seemingly spread

around the listener by two or more related au-

dio signals. In practice, stereo often is taken to

simply mean two channels.

Electrical or sound level in an audio system.

Perhaps the only thing that some bands have

too much of.

XLR connector

A three-pin connector used in audio for

transmitting a balanced signal. Sometimes re-

ferred to as a Cannon connector, named for the

manufacturer who first popularized the three-

pin connector.

sweep EQ

An equalizer that allows you to “sweep” or

continuously vary the affected frequency of one

or more sections.

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APPENDIXC:Connectors

“XLR” CONNECTORS

• Balanced mono circuits. When wired as a

balanced connector, a 1⁄4" TRS jack or plug is

connected tip to signal high (hot), ring to sig-

nal low (cold), and sleeve to ground (earth).

This is the application used for the inputs to

Mackie amplifiers.

Mackie amplifiers use 3-pin female “XLR”

connectors on each input, with pin 1 wired to

the grounded (earthed) shield, pin 2 wired to

the “high” (”hot” or positive polarity) side of

the audio signal, and pin 3 wired to the “low”

(“cold” or negative polarity) side of the signal

(Figure A). All totally above-board and in full

1⁄4" TS PHONE PLUGS AND JACKS

“TS” stands for Tip-Sleeve, the two connec-

tions available on a “mono” 1⁄4" phone jack or

plug (Figure C). TS jacks and plugs are used

in many different applications, always unbal-

anced. The tip is connected to the audio signal

and the sleeve to ground (earth). Some

examples:

SHIELD

HOT

COLD

SHIELD

COLD

HOT

• Unbalanced microphones

• Electric guitars and electronic

instruments

SHIELD

COLD

HOT

• Unbalanced line-level or speaker-level

connections

Figure A: XLR Connectors

accord with the hallowed standards dictated

by the AES (Audio Engineering Society).

Use a male “XLR”-type connector, usually

found on the nether end of what is called a

“mic cable,” to connect to a female XLR jack.

SLEEVE

TIP

TIP (HOT)

SLEEVE (SHIELD)

Figure C: TS Plug

1⁄4" TRS PHONE PLUGS AND JACKS

“TRS” stands for Tip-Ring-Sleeve, the three

connections available on a “stereo” 1⁄4" or “bal-

anced” phone jack or plug (Figure B). TRS

jacks and plugs are used in several different

applications:

UNBALANCING A LINE

In most studio, stage, and sound reinforce-

ment situations, there is a combination of

balanced and unbalanced inputs and outputs

on the various pieces of equipment. This

usually will not be a problem in making

connections.

RING SLEEVE

SLEEVE RING TIP

TIP

RING (COLD)

• When connecting a balanced output to

an unbalanced input, be sure the signal high

(hot) connections are wired to each other, and

that the balanced signal low (cold) goes to the

ground (earth) connection at the unbalanced

input. In most cases, the balanced ground will

also be connected to the ground at the unbal-

anced input. If there are ground-loop problems,

this connection may be left disconnected at the

balanced end.

TIP (HOT)

SLEEVE (SHIELD)

Figure B: ¹⁄4" TRS Plugs

• Stereo Headphones, stereo microphones

and stereo line connections. When wired for

stereo, a 1⁄4" TRS jack or plug is connected tip

to left, ring to right and sleeve to ground

(earth).

• Unbalanced Send/Return circuits. When

wired as a send/return “Y” connector, a 1⁄4" TRS

jack or plug is connected tip to signal send

(output from mixer), ring to signal return

(input back into mixer), and sleeve to ground

(earth).

• When connecting an unbalanced output

to a balanced input, be sure that the signal

high (hot) connections are wired to each

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other. The unbalanced ground (earth) connec- SPEAKONS

tion should be wired to the low and the ground

Speakon^®connectors have become popular

connections of the balanced input. If there are

ground-loop problems, try connecting the un-

balanced ground connection only to the input

low connection, and leaving the input ground

connection disconnected.

with many loudspeaker manufacturers be-

cause they provide a quick, yet safe and secure

method of connecting speaker cables. The

M•1400 is outfitted with Speakon connectors

(Figure G) instead of the 1/4" TS jacks pro-

vided on the M•1200. Speakon connectors

have a twist-locking mechanism that prevents

them from being pulled out accidentally. Plus,

they are capable of handling high currents, and

meet IEC 65 and IEC 348 safety requirements.

Pin 1+ is positive (+) and Pin 1– is negative (–).

• In some cases, you will have to make up

special adapters to interconnect your equip-

ment. For example, you may need a balanced

XLR female connected to an unbalanced 1⁄4"

TS phone plug. The balanced-to-unbalanced

connection has been anticipated in the wiring

of Mackie jacks. A 1⁄4" TS plug inserted into a

1⁄4" TRS balanced input, for example, auto-

matically unbalances the input and makes all

the right connections. Conversely, a 1⁄4" TRS

plug inserted into a 1⁄4" unbalanced input

automatically ties the ring (low or cold) to

ground (earth).

MONO

BRIDGE

–

SPEAKER OUTPUTS

BINDING POSTS

Figure G: Speakon Connectors

Binding posts provide a number of different

methods for connecting speaker wire to the

outputs of the amplifier. For fixed installations,

you can use bare wire (Figure D), or wire ter-

minated with spade lugs (Figure E).

1/4"

Figure D: Binding Posts with Bare Wire

Figure E: Binding Posts with

Spade Lug

For portable applications, the binding posts

accept single or double banana plugs (Figure

F). They provide a method of quickly connect-

ing and disconnecting speaker cables to and

from the amplifier. Double banana plugs have a

tab on one side to indicate the ground (GND)

side of the connector. This side connects to the

black (–) binding post terminals on the amplifier.

Figure F: Binding Posts with Double Banana Plug

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APPENDIXD:ArcaneMysteriesIlluminated

Balanced Lines

sleeving on the drain wire (the one that

connects to pin 1) to prevent it from

contacting the connector shell.

Balanced lines offer increased immunity

to external noise (specifically, hum and buzz).

Because a balanced system is able to minimize

noise, it is the preferred interconnect method,

especially in cases where very long lengths of

cable are being used. A long unbalanced cable

carries with it more opportunity for noise to get

into a system — having balanced inputs means

very little noise will enter the system via snakes

and other cables that typically must run a long

length.

2. Don’t connect the XLR connector shell to

pin 1 of the XLR connector. Doing so is an

invitation for a ground loop to come

visiting.

3. Do ensure that your speaker lines and AC

power lines are physically separated from

your microphone lines.

4. If you use floor pockets, use separate

pockets for inputs and speakers, or put the

connectors on opposite sides of the box so

that they may be shielded separately.

5. If your speaker lines run in the open, they

should be twisted pairs, at least 6 twists per

foot. Otherwise, run the speaker lines in

their own conduit. (Of course, conduit is not

too practical for portable systems, heh-heh.)

A balanced line is a three-

wire system where two wires

carry the signal and the third

is a ground wire that shields

the inner conductors from

EMI. The two inner conductors carry the same

signal, but with opposite polarity. The balanced

input amplifies only the difference between the

two conductors. But a signal that is common

to both conductors, and in phase, is rejected

(canceled out) at the balanced input. This

includes hum from AC lines or other EMI

induced noise.

An unbalanced line does not have this

noise-rejecting capability because it has only

two conductors. One conductor carries the sig-

nal and the other is a ground wire that shields

the inner conductor. Any hum or EMI noise

that gets through the shield is added to the sig-

nal and amplified at the unbalanced input.

Often the hum can be louder than the signal itself!

6. Minimize the distance between the power

amplifiers and the speakers.

7. Use heavy gauge, stranded wire for speaker

lines. Ideally, the wire resistance should be

less than 6% (0.5 dB power loss) of the load

impedance. Remember that the actual run

is twice as long as the physical length of

the run. See below.

Maximum wire run for 0.5dB power loss in feet

wire

res. per

Ω

gauge 1000 ft.

1.00

1.59

2.5

60 120 240

75 150

“Do’s” and “Don’ts” of Fixed Installations

If you install sound systems into fixed instal-

lations, there are a number of things that you

can do to make your life easier and increase

the likelihood of the sound system operating

in a predictable manner. Even if you don’t do

fixed installations, these are good practices for

any sound system.

4.02

8. Ensure that the electrician uses the star-

ground system for the safety grounds in

your electrical system. All of the audio

system grounds should terminate at the

same physical point. No other grounds may

come in contact with this ground system.

9. Ensure that the AC power feeds are

connected to the same transformer, and

ideally, the same circuit breaker.

1. Do use foil-shielded snake cable for long

cable runs. Carefully terminate each end,

minimizing the amount of shielding

removed. Protect the exposed foil shield

with shrink sleeving or PVC sleeving.

Prevent adjacent shields from contacting

each other (electrically). Use insulating

10. Walk outside — look at the horizon. See

any radio towers? Locate potential sources

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of RF interference and plan for them

before you begin construction. Know the

frequency, transmitter power, etc. You can

get this information by calling the station.

Remember that many broadcast stations

change the antenna coverage pattern and

transmitter power at night.

Here are some guidelines:

1. Use balanced lines if at all possible. They

provide better immunity to induced noise

and ground loops. Remember that you can

balance a line by inserting in-line a piece of

equipment that has a balanced output.

2. Avoid using three-phase power lines since

they are usually used for air conditioning

and other heavy power equipment. If using

240VAC single phase with center-ground

power, connect all audio equipment to one

side of the AC power, and all lighting and

other equipment to the other side.

11. Don’t use hardware-store light dimmers.

12. Don’t allow for anything other than micro-

phone inputs at stage/altar locations.

Supplying line inputs at these locations is

an invitation for misuse. Make all sources

look like microphones to the console.

3. Be sure all AC outlet safety grounds are

connected to one common point in a star

ground arrangement. This common ground

point should then tie back to earth ground

at the service entrance by one heavy

stranded wire, #2 gauge or larger.

13. Balance (or at least impedance balance)

all connections that are remote from the

console’s immediate location.

14. If you bridge an amplifier, don’t use 1⁄4"

phone plugs for speaker connectors.

4. Don’t cut the third pin off the power cord.

Carry some ground-lifter adapters and use

them only if you have to plug into an

ancient two-wire outlet.

5. Cables that are too long are less likely to

pick up hum if you uncoil them in their

entirety, and then find a place to stow the

excess. Leaving the excess coiled only helps

the cable pick up hum more efficiently.

6. If you bundle your cables together, don’t

bundle AC wiring and audio wiring to-

gether. Bundle them separately.

7. If your sound system insists on humming,

you may need to teach it the words.

Grounding

Grounding exists in your audio system for

two reasons: product safety and noise reduc-

tion. The third wire on the power cord exists

for product safety. It provides a low-resistance

path back to the electrical service to protect

the users of the product from electrical shock.

Hopefully, the resistance to ground through the

safety ground (third wire) is lower than that

through the user/operator to ground. If you re-

move this connection (by breaking or cutting

the pin off, or by using a ‘ground cheater’), this

alternate ground path ceases to exist, which is

a safety hazard.

The metal chassis of the product, the

ground connections provided by the various

connectors, and the shields within your con-

necting cables provide a low-potential point for

noise signals. The goal is to provide a lower im-

pedance path to ground for noise signals than

through the signal wiring. Doing so helps

minimize hum, buzz, and other extraneous

non-audio signals.

Many “authorities” tell you that shields

should be connected only at one end. Some-

times this can be true, but for most (99%)

audio systems, it is unnecessary. If you do ev-

erything else correctly, you should be able to

connect every component of your audio system

using standard, off-the-shelf connecting cables

that are available at any music store.

Optimizing Sound System Levels

In a full-blown (not fully blown) sound

system, the signal level can be controlled or

adjusted at many different points throughout

the signal chain. The best system performance

is achieved when the dynamic range of the

system is maximized, thus reducing noise and

allowing a nominal signal level to be used with

maximum headroom. Whatzat!?

Dynamic range is the difference between

the noise floor and the maximum undistorted

signal level capability of the component. The

greater the dynamic range, the better the sig-

nal to noise ratio, because the nominal signal

level can be set at a higher amplitude and the

noise tends to get buried underneath the sig-

nal. Headroom is the difference between the

maximum undistorted signal level capability of

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the component and the nominal signal level.

It is important to maintain a reasonable

amount of headroom so that the dynamic

Next comes the output level of the channel,

controlled by a fader or rotary gain control.

Faders usually have an indication in the graph-

transient peaks of the musical program can be ics that shows the normal or nominal setting

reproduced without clipping. 10 dB of head-

room is usually adequate, but some program

material may require up to 20 dB.

for the fader. This setting is usually 10 or 12 dB

below the maximum output level of the chan-

nel. This provides the headroom needed to

reproduce the transient peaks associated with

music. If the channel has a meter, you can use

that to visually confirm that the nominal output

level of the channel is around “0” on the meter.

Next set the master output level (fader)

control on the mixer to the nominal level indi-

cation next to the control. Again, this should be

at least 10 dB below the maximum output level

of the mixer. You can double check the actual

output signal level if there is an output meter

on the mixer. On most professional equipment,

this nominal output level will be +4 dBm

(1.23V rms into 600 ohms).

The output of the mixer may drive a power

amplifier directly, or it may go through a signal

processor first (i.e., equalizer, compressor lim-

iter, crossover). Determine the maximum

output capability of the signal processor.

Hopefully, it can produce at least +14 dB to

maintain the required 10 dB of headroom.

Chances are it can produce considerably more

than that (like +20 dB to +24 dB). If 10 dB of

headroom is not available, you’ll have to intro-

duce a resistive pad between the mixer and the

signal processor to reduce the signal level from

the mixer so it is at least 10 dB below the maxi-

mum output of the processor.

40dB

MAXIMUM OUTPUT LEVEL

30dB

(M•1200 = 400W/4Ω)

HEADROOM

20dB

NOMINAL LEVEL (25W/4Ω)

10dB

DYNAMIC

RANGE

–10dB

–20dB

–30dB

–40dB

–50dB

–60dB

SIGNAL TO NOISE

RATIO

–70dB

–80dB

NOISE FLOOR

Dynamic Range

The best way to accomplish this goal is to

optimize the input and output levels for each

component in the system. It is best to start at

the beginning of the chain (the microphone)

and work your way to the end (the speakers).

The following procedure details how to opti-

mize a sound system with 10 dB of headroom.

A microphone is connected to the mic input

on the mixing console. The gain of the mic

preamp circuit, sometimes called Mic Trim,

should be adjusted so that the loudest micro-

phone signal is just below the overload point

of the preamp. Most mixing consoles provide a

mic preamp clipping indicator or level meter-

ing of some kind to optimize the mic preamp.

If the processor has enough headroom, set

the level controls to unity gain, so with a +4 dB

input it produces a +4 dB output. Keep in

mind that if this is an equalizer, and you’ve

boosted several frequency bands, the nominal

output level may be more than +4 dB because

of the extra energy the processor is adding to

those frequencies. It may be necessary, in that

case, to reduce the level controls a few dB

below unity.

The M•1200/M•1400 amps are designed to

accept a nominal +4 dB input signal. Set the

GAIN controls fully clockwise. This will pro-

vide the best signal-to-noise ratio and available

headroom for the amplifier.

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Biamplified and Triamplified Systems

Most speaker systems in use today are of

the two-way or three-way variety. Cone speak-

Biamplified and triamplified systems use

separate power amplifiers to power each indi-

vidual low-frequency and high-frequency

ers are good at reproducing low and mid-range driver. An electronic crossover (a.k.a. active

frequencies, but not high frequencies. Like-

wise, compression drivers are good at

reproducing high frequencies, but definitely

not low frequencies. This is why two-way,

three-way and even four-way speaker systems

were developed — to improve the efficiency

of each individual driver by requiring it to

reproduce only the frequencies that it repro-

duces best.

crossover) is located between the signal source

and the power amplifier. The advantages of

this method include 1) increased headroom

available from each amplifier, since they’re am-

plifying only a portion of the entire audio

spectrum; 2) improved damping factor be-

cause the amplifier output is connected

directly to the driver; 3) improved efficiency

because there are no passive resistors to dissi-

pate heat; and 4) flexibility to choose the

One method of accomplishing this is

through the use of a passive crossover network optimum crossover frequency and crossover

between the amplifier and the speaker(s).

Often the passive crossover is built into the

cabinet along with the various drivers. The

crossover divides the high-level speaker signal

into frequency bands, which are then directed

to the appropriate driver. There are some

drawbacks to this method, however. The pas-

sive crossover adds reactance to the load that

the amplifier sees, which can affect the damp-

ing. Power is wasted as heat across the

resistors in the crossover, reducing the

amount of amplifier power available to the

drivers themselves.

slope for the individual drivers in the system.

TWO-WAY SPEAKER CABINET

HIGH-LEVEL

HIGH FREQUENCIES

PASSIVE

FR SERIES

POWER AMPLIFIER

(STEREO MODE)

TO TWEETER

CROSSOVER

LOW FREQUENCIES

TO WOOFER

CH 1

OUT

FROM SIGNAL SOURCE

(MACKIE MIXING CONSOLE)

–

TWO-WAY SPEAKER CABINET

CH 2

OUT

FROM SIGNAL SOURCE

(MACKIE MIXING CONSOLE)

HIGH-LEVEL

HIGH FREQUENCIES

PASSIVE

TO TWEETER

CROSSOVER

LOW FREQUENCIES

TO WOOFER

Passive Crossover System

FR SERIES

POWER AMPLIFIER

(STEREO MODE)

FROM SIGNAL SOURCE

(MACKIE MIXING CONSOLE)

CH 1

INPUT

TO HIGH-FREQUENCY

CH 1

OUT

AMPLIFIER

LOW-LEVEL

3-WAY ACTIVE

CROSSOVER

–

CH 2

INPUT

TO MID-FREQUENCY

AMPLIFIER

CH 2

OUT

MID

FR SERIES

POWER AMPLIFIER

(BRIDGE MODE)

FR SERIES

POWER AMPLIFIER

(STEREO MODE)

FROM SIGNAL SOURCE

(MACKIE MIXING CONSOLE)

CH 1

INPUT

TO LOW-FREQUENCY

AMPLIFIER

CH 1

INPUT

WOOF

TO HIGH-FREQUENCY

AMPLIFIER

CH 1

LOW-LEVEL

OUT

–

2-WAY ACTIVE

CROSSOVER

OUT

–

WOOF

CH 2

INPUT

–

TO LOW-FREQUENCY

AMPLIFIER

CH 2

–

CH 2

OUT

Biamplified System with Active Crossover

Triamplified System with Active Crossover

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APPENDIXE: TechnicalInfo

DO THE MATH: OHMS, LOADS AND SUCH

Remember: As the load gets “heavier,” its

“Parallel” means that the positive amp out-

value in ohms goes down. For instance, a

2-ohm speaker load is twice as “heavy” as a

4-ohm load. An ohm is a unit of resistance —

the more ohms, the more resistance (imped-

ance). The more the resistance, the less the

power. It can all seem backwards at first. Just

remember that a dead short means no resis-

tance at all, or zero ohms.

put connects to the positive terminals of all the

speakers, and the negative amp output con-

nects to the negative terminals of all the

speakers. If one speaker fails in a parallel con-

figuration, the others will still work, but the

load will change. That lets you breathe a little

easier (the show will go on), except that you

may have a dead speaker and not even know it.

Calculating parallel loads is also easy, as

Since you’re in the biz (or you are now,

since you just bought an amp), you probably

long as each speaker has the same value —

own a volt/ohm meter (or DVM, for Digital Volt just divide the value by the number of speak-

Meter). It’s an indispensable tool for anyone

working with speakers and such. If you don’t

own a meter, go out and get one right now —

we’ll wait.

ers. For instance, four 8-ohm speakers,

connected in parallel, will equal 2 ohms

(8 / 4 = 2). If the loads aren’t all the same, the

formula gets a little more complicated, but

nothing that you can’t do with a simple calculator.

If you’re just dealing with one speaker (or

cabinet) per output, the load in ohms will be

printed on it somewhere. That’s your load. You

can confirm this with the volt/ohm meter you

just bought — set it for ohms, set it for the

lowest range (unless it’s an autoranging

meter) and measure across the speaker termi-

nals. It may not agree exactly; a speaker rated

at eight ohms may read between 5 and 7 ohms.

(If it’s a multiple-driver speaker with a built-in

passive crossover, this method won’t work.)

If you’re driving an assortment of speakers

(or cabinets), things can get complicated.

There are two basic ways of linking multiple

loads (speakers in this case): series and parallel.

“Series” means that the positive amp output

connects to the first speaker’s positive termi-

nal, the first speaker’s negative terminal

connects to the second speaker’s positive ter-

minal, the second speaker’s negative terminal

goes to the third, and so on, until the chain

ends at the amp’s negative output. Series con-

nections are not normally used in PA

. . .

There are other, more complicated configu-

rations, like series-parallel (using a combination

of series and parallel links to arrive at a de-

sired load) and parallel configurations of

unmatched loads (usually not recommended).

But rather than get too deep into this, let’s just

summarize the basics, as they apply to you and

your M•1200/M•1400 Power Amplifier:

• As a load gets “heavier,” its impedance in

ohms decreases.

• The lower the impedance (ohms), the

higher the power: The M•1200 has 600 watts

(per side) with a 2-ohm load, 400 watts with

4 ohms, and 225 watts with 8 ohms.

• Do not connect a load of under 2 ohms

(in STEREO and MONO mode) or 4 ohms

(in BRIDGE mode).

• Never plug amplifier outputs into any-

thing except speakers (unless you have an

outboard box designed to accept speaker levels).

• Never play good music through bad speak-

ers. You may, however, play bad music through

good speakers (but only on odd-numbered

Fridays).

applications because it ruins the amplifier’s

ability to damp (control) the speakers.

Doing load calculations with series configu-

rations is easy — just add the loads. For

instance, four 8-ohm speakers, connected in

series, will equal 32 ohms (8 + 8 + 8 + 8 = 32).

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SPECIFICATIONS

Continuous Average Output Power, both

channels driven:

Channel Separation:

M•1200

> 80 dB @ 1kHz

225 watts per channel into 8 ohms from 20Hz to 20kHz,

with no more than 0.025% THD

Damping Factor:

> 350 from 0 to 400Hz

400 watts per channel into 4 ohms from 20Hz to 20kHz,

with no more than 0.050% THD

Input Impedance:

20kΩ balanced bridging

600 watts per channel into 2 ohms from 20Hz to 20kHz,

with no more than 0.095% THD

Input Sensitivity:

Bridged mono operation:

1.23 volts (+4 dBu) for rated power into 4 ohms

800 watts into 8 ohms from 20Hz to 20kHz, with no more

than 0.050% THD

Gain:

30.25 dB (32.5V/V)

1200 watts into 4 ohms from 20Hz to 20kHz, with no

more than 0.095% THD

Maximum Input Level:

M•1400

9.75 volts (+22 dBu)

250 watts per channel into 8 ohms from 20Hz to 20kHz,

with no more than 0.012% THD

Rise Time:

< 4.4µs

425 watts per channel into 4 ohms from 20Hz to 20kHz,

with no more than 0.025% THD

Slew Rate:

Voltage Slew Rate > 50V/µs

630 watts per channel into 2 ohms from 20Hz to 20kHz,

with no more than 0.050% THD

> 100V/µs bridged

Bridged mono operation:

Current Slew Rate > 32A/µs at 2Ω

850 watts into 8 ohms from 20Hz to 20kHz, with no more

than 0.025% THD

CMRR:

> 40 dB, 20Hz to 20kHz

1260 watts into 4 ohms from 20Hz to 20kHz, with no

more than 0.050% THD

Load Angle:

8(+jω) time independent at 8Ω

4(+jω) time dependent, T > 6 min. at 4Ω

2(1+jω) time dependent, T > 2 min. at 2Ω

Maximum Power at 1% THD:

280 watts per channel into 8 ohms

480 watts per channel into 4 ohms

700 watts per channel into 2 ohms

960 watts into 8 ohms bridged

Transient Recovery:

< 1µs for 20 dB overdrive @ 1kHz

1400 watts into 4 ohms bridged

Note: The M•1200/M•1400 power amplifiers draw large

amounts of current from the AC line with continuous

sine wave testing. Accurate measurement of power re-

quires a steady and stable AC supply. This means the

line impedance must be very low to insure that the peak

AC line voltage does not sag to less than 97% of its value.

High Frequency Overload and Latching:

No latch up at any frequency or level.

High Frequency Stability:

Unconditionally stable driving any reactive or capacitive

load.

If driving highly reactive loads, we recommend that the

limiter circuit be engaged.

Turn On Delay:

3 seconds

Power Bandwidth:

20Hz to 70kHz (+0, –3 dB)

Variable High-Pass Filter:

10Hz (Off) to 170Hz, 2nd Order Bessel

Frequency Response:

20Hz to 40kHz (+0, –1 dB)

10Hz to 70kHz (+0, –3 dB)

Subwoofer Low-Pass Filter:

Switched: 63Hz/125Hz, 3rd Order Bessel

Distortion:

Constant Directivity High Frequency Boost:

2.5kHz to 6kHz (+3 dB points)

6 dB/octave high-frequency shelving filter,

(shelving occurs at approximately 30kHz)

THD, SMPTE IMD, TIM

< 0.025% @ 8Ω

< 0.050% @ 4Ω

< 0.150% @ 2Ω

Signal-to-Noise Ratio:

> 107 dB below rated power into 4 ohms

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Limiter Section:

AC Line Power:

Complementary Positive and Negative Peak Detecting

120VAC, 60Hz

Europe

Japan

Korea

240VAC, 50/60Hz

100VAC, 50/60Hz

240VAC, 60Hz

Indicators:

6 meter LEDs per channel

SIG (Signal Present), –20, –9, –6, –3, OL (Overload)

AC Drop-out Voltage:

At approximately 50% of rated line voltage

CH 1 & 2

PROTECT LEDs

SHORT LEDs

Physical:

TEMP STATUS

Height

Width

Depth

Overall Depth

Handle Depth

Weight

3.5 inches (89mm)

19.0 inches (483mm)

15.25 inches (387mm)

16.25 inches (413mm)

1.25 inches (32mm)

36 pounds (16.3kg)

COLD/HOT LEDs

Power Consumption:

65 watts at idle

900 watts with musical program fully loaded

(2 ohms per side, or 4 ohms bridged)

550 watts with musical program fully loaded

(4 ohms per side, or 8 ohms bridged)

850 watts at full power into 8 ohms

(continuous sine wave)

Mackie Designs is always striving to improve our

products by incorporating new and improved materials,

components, and manufacturing methods. Because we’re

always trying to make things better, we reserve the right

to change these specifications at any time without notice.

1500 watts at full power into 4 ohms

(continuous sine wave)

2500 watts at full power into 2 ohms

(continuous sine wave)

17.25" (43.8cm)

M•1200/1400

WEIGHT

36 lbs.

(16.3 kg)

FULL SYMMETRY DUAL DIFFERENTIAL HIGH CURRENT DESIGN

PROFESSIONAL POWER AMPLIFIER

GAIN/dB

–3

INTERNAL STATUS

–6

–9

–6

–9

PROTECT

SHORT

–20

TEMP STATUS

OFF

1& 2

COLD

HOT

SENSITIVITY 1.23v (+4dBu)

SIG

POWER

19.00" (48.3cm)

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BLOCK DIAGRAM

M•1200/ M•1400

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COLOPHON

Manual written by Jeff Gilbert and Dave

Franzwa, with tidbits borrowed from almost

everywhere, including huge chunks of techni-

cally baffling text contributed by Rick Chinn.

Manual then defaced with proofreading pens in

the hands of Mackie’s legendary Tech Support

staff (Paul Larson), New Products Engineering

staff (Cal Perkins and Cameron Jones), and

our incomparable Art Department (Sara

Delahan). Back cover collage composed by

Jayme Delma.

Manual composed with No. 4 blue sidewalk

chalk on the banks of beautiful Sammamish

Slough by Mackie’s notorious Technical Writing

staff, then converted to this amazing piece

of work using a 13-story 1000 gigawhat

Macintosh, powered by its own dedicated AC

supply with extensive voltage regulation and

noise filtering to insure pure, undistorted text.

Please, feel free to let us know if you find an

error or stumble over a confusing paragraph.

Thank you for reading the entire manual (we

know you have, or you wouldn’t be here).

Mackie, The Running Man, and FR Series

are either trademarks or registered trademarks

of Mackie Designs Inc.

Speakon is a registered trademark of Neutrik.

All other brand names mentioned are

registered trademarks or trademarks of their

respective holders, and are hereby acknowledged.

Printed in the U.S.A.

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